This is set a little before Sentinel Prime came back with the Decepticon hostages, which I think is a good explanation for why Beachcomber and Cosmos were so far apart in the crowd scene, when I think they have a father/son relationship.
If there's anything he shouldn't have done, it was lose sight of Beachcomber.
Kalis was a BIG city, even bigger than Omnicron! And Omnicron was probably one of the biggest cities he had ever been to so far, with Beachcomber. He was so amazed by all of the 'bots that just walked from place to place everywhere, all minding their own business with their default face plastered on their faceplates. Some of them smiled, others frowned, and some had little to no emotion on their face at all. For a moment, Cosmos tried to match the faces on them to the person's personality, but then he thought better of it, Beachcomber had a frown as his default; and he wasn't a fusspot or a naysayer or a worrywart or anything. Cosmos wondered how he looked like to other people. Maybe Beachcomber would tell him… Oh yeah, that's right. Beachcomber wasn't around.
At first, Cosmos wasn't too surprised by this. He always ended up wandering off somewhere, but usually he'd just float himself up somewhere and stay there. Sometimes he ended up moving on that invisible stand that he made for himself, though he never pushed or pulled it. Sometimes it just took him somewhere, anywhere really. Cosmos liked it when it did that; he got to see new things. Though, so far, none of the cities Beachcomber had taken him to were very attention-grabbing; just a bunch of metal or rocks. Sometimes there were bright and pretty lights somewhere, but after a while it just got dull seeing metal buildings everywhere.
But he couldn't make an invisible-floating-stand-thing like he usually did, because the people here moved too fast for him. Apparently something was going on, and it was getting close to some sort of big performance thing or something. Well, whatever was going on, Cosmos didn't care about it. He was so lost he wasn't even sure if he was still in the same city! There was nothing at all that he recognized, just a whole lot of building and mechs and femmes all running around and bumping into him. Cosmos wondered if some people would trip over him. He was kinda short… well, not too short, but short enough that almost everyone had to look down to see him. Well, his optics met about shoulder-level with the scouts, so they didn't have to look as far down to see him.
The more Cosmos looked around, the scarier everybot seemed to be. More and more he found bots with frowns on their faceplates, some of them so deep he could have sworn they were angry at something, thinking about things that made them angry. Beachcomber never thought of things that made him angry. He usually just thought of nothing, nothing at all. It was only when Cosmos said something that Beachcomber got a random thought into his head. Sometimes he'd go on and on about the color spectrum or stare at something until he made a comment.
Cosmos wished he was here right now; he wanted to hear Beachcomber say something about the colors of the 'bots around them, tell him why there were so many lights on now (which made it really hard for him to see), or tell him why there were these little animal-shaped Autobots wandering around the street. There were so many things he didn't know, he hated being a sparkling. He was too scared to ask the frowning 'bots if they could tell him where Beachcomber was, or to give him a shoulder to cry on. He tried not to cry. He'd fill up his bubble with coolant, and that wasn't a good thing. He didn't need another problem to add to all the others he was having today.
At last, Cosmos couldn't walk anymore. As soon as he found a seat somewhere, he shuffled over to it and sat down, grateful for the rest. Everyone here seemed so busy, and so focused on other things that they had to do. It kinda stunk, having to devote your entire life to work and work and more work. Where was the breathing space? Cosmos probably wouldn't survive without his bubble, maybe, but at least his bubble was made out of glass, not like the big black boxes everyone else put on. Figuratively, of course.
Beachcomber wasn't like that. Sure, his default face was a frown, but that was only because it was easier to hold his face like that, for whatever reason. Cosmos had a faceplate stuck on, so he didn't have an expression. But he figured he looked kinda triangular, maybe a bit like he was frowning, too. Or maybe he was smiling? He'd really have to ask Beachcomber what his face looked like. If he ever found him.
The more he thought about him, the more things hurt a little inside. He felt really lost and alone; as though no one else would understand him. Beachcomber probably wouldn't like him feeling like this. Beachcomber always made sure only good things happened to people, be they an overworked businessman or a runaway sparkling. Was Cosmos a runaway sparkling? He always wandered off somewhere that caught his interest, losing interest in things if they didn't interest him or if he didn't want to be part of a fight that was nearby. Sometimes he'd try to talk to someone about the fight they were having, but he never got through to anyone. Always brushing him off.
He'd always told himself he'd try again later. But when was later? Later wasn't now, that was for sure. If he wanted to find Beachcomber, he'd have to do it now, and not later. Later never came, anyway, and soon never came quickly enough. Yeah! He'd find Beachcomber! All he had to do was… what? Ask someone? Okay… what's the harm in trying, right?
Hey! There's one now! It looked like another scout, same short body-type, only he looked a little different… rounder? Maybe he was built with circles in mind or something. But he seemed nice enough. If he just asked him, he was probably going to get a straight answer. Or he would blow up in his face in anger, saying that he was stupid for not knowing where is own mentor was. Cosmos felt a chill slide down his chassis, and he got scared. Stop that! Now wasn't the time to be scared! All he had to do was go up and ask! But what would he ask? Where Beachcomber was? He didn't know who Beachcomber was! Oh…
Agh! He's looking this way! How did he know Cosmos was looking at him? Oh no oh no oh no! What was he going to do? He was just standing stupidly in the entrance to a restaurant or something, frozen. What was he supposed to do? Run away? Would he chase after him, demanding to know why he was staring at him? Was he—AGH! He's getting closer. Cosmos never felt so scared in his life. This was the first time he had to talk to someone without Beachcomber around. What was he going to say? What was he going to do? He wished Beachcomber were around now more than ever. He'd know what to say. If there was anything Beachcomber knew, it was what to say to someone who asked him a question. He wasn't afraid of not knowing the correct answer, he just flat-out said so if he didn't know something. Maybe Cosmos should do that…
"Hey, are you okay little guy?" Oh dear…
"Um… I… I'm l-lost." Cosmos finally managed to sputter out, bowing his head low and staring at his fingers, twiddling them in and out of each other and tapping them. He'd seen others do that, but he never really felt the need to do it himself. Only now was a very good time to do it, since he was real nervous. He was talking to a stranger in a city he had never been to! Of course he would be nervous!
The scout bent down a little and put a hand on his shoulder. Cosmos glanced at it for a moment, and stared back at his face. He had wide eyes and something on his lips. Did he have an infection? He had stretched out horn-things on his head, and he had a very square head altogether. Cosmos got a little confused, now doubting if he was healthy.
"There there, little guy. You'll be fine. Are you new to Kalis?" He asked. Cosmos was at a loss for words, now wondering if he… she was one of those 'femme' things. He didn't understand was a femme was yet, since Beachcomber didn't seem to understand them either. The only time Beachcomber ever said anything about femmes was that they shouldn't be treated any differently than any other 'bot. Oh wait… she was waiting for him to answer.
"Y-Yeah… I'm new to Kalis. Um… Ha-have you… Uh…" Cosmos still didn't know how to ask his question. What was he supposed to say? Where Beachcomber was? Where his mentor was? If they could him find him? But that didn't seem right. She wouldn't know who Beachcomber was, and Cosmos didn't know how to describe him without getting sad and wanting to cry. And he couldn't cry, because his bubble would get filled with coolant. He didn't know what would happen if his bubble got filled with coolant. He didn't even know why he had a bubble.
Wait… couldn't he just…? Well, there was no harm in trying, right? This femme seemed to really want to help him… He did it anyway, even though he wasn't entirely sure if he wanted to share something sad. Usually when he shared his visions, they were happy. When he sent them to Beachcomber he always dazed off somewhere and smiled, before giving him a hug and thanking him for the 'gnarly visions'. The only time he sent them to someone else was Hot Shot back on Iacon, and that was to prove a point. He wondered how this femme would react to him sending her all of his sad feelings this way.
He watched her optics get all glazed over the way Hot Shot's did. She stared off into some other place, and her faceplate twisted into a frown. Cosmos felt a little better when he shared it, but he saw what she saw too. This time he didn't have to say anything, he just had to think of it. He just thought of what was making him sad, and sent it to her. He shared how scared he felt, and all those frowning faces and scary eyes that didn't even look at him when he tried to ask them where he was or if they could help. He was too scared to ask. He was lost, and he just wanted to go home. And his home wasn't some dorm in a building or anything. His home was next to Beachcomber.
Cosmos didn't want to cry anymore, though. Now the femme was crying, and Cosmos stopped. He didn't want to make her cry! He just wanted to let her know what he was going through… He didn't think anyone else would cry because of it. The femme hugged him tightly, and out of nowhere. Cosmos wasn't sure how to react to this, but he hugged her back anyway. It was nice to get a hug; he felt much better after he got a hug from somebody. Especially from Beachcomber. Beachcomber always gave the best hugs.
"Oh, you poor little sparkling…" the femme sniffed a bit, trying to hold back buildup she must have gotten. She let him go, and Cosmos stood up straight, determined to be strong. If he could go without crying, then he could help her, too! She didn't have to cry for something that he was going through. Cosmos curled his hands into fists and nodded at her, trying to make himself look stronger. And to be honest, he felt a little stronger too. Everything was getting a bit better now, so he had no reason to want to cry anymore! He knew she'd help him. She told him so;
"C'mon. Let's go find Beachcomber."