Jack sprang into action and raced from his office, grabbing the nearest fire extinguisher as the alarms went off in the Hub. He hesitated momentarily when the intruder alert began sounding at the same time. When it rains it pours he thought, patting the comforting bulk that rested against his hip, and slowed his headlong pace to a cautious reconnaissance.
There was no one to back him up, as Ianto and Gwen had left for the evening, and suddenly he was feeling very isolated and vulnerable.
He leaned to the side of the closed door and cautiously turned the knob, pushing the door open a few centimeters. Squaring his shoulders and taking a deep breath, he used the fire extinguisher as a weapon as he kicked out with his front foot and stormed into the room, ready to fight.
His face broke into a large grin when he saw the culprit responsible for the racket. "I should have known," he laughed, watching the Doctor furiously attempt to blow out the small inferno he'd created. His hair and arms flailed madly and seemed to fuel the fire that engulfed a large rectangular area.
"Don't just stand there—" the Doctor yelped as the flames grew higher, forcing him to step back from the heat.
Jack pulled the pin, heard the metal ping as it bounced off the floor and gently squeezed the trigger, blanketing the scene in thick white foam. Both alarms shut off simultaneously leaving only the hiss of the dying flames and the Doctor's trainers squish as he stepped back from the mess.
"Flame retardant frosting, needs a bit of work," mused the Doctor, wiping foam from his eyes with two fingers, his brown eyes blinking owlishly under the white mask. "Hello, Jack," he said enthusiastically, looking up at the other man with childlike glee.
Jack chuckled and shook his head, setting the fire extinguisher onto the ground. "To what do I owe this visit?" Jack eyed the Time Lord warily; there was always a reason for his visits.
"Well—" shrugged the Doctor, "Thought we'd catch up on a few celebrations, for old times sake." The Doctor rubbed the back of his neck, surveying the remains of the cake and grimaced.
"I don't recall us ever celebrating anything before," Jack reminded him, his hands on his hips and head turned slightly, waiting for the other shoe to drop.
"Into time and space?" the Doctor prompted, and watched as Jack was suddenly reminded of traveling with another incarnation of the man standing before him.
He still wasn't sure why the Doctor had decided to drop in on him, but thought he'd test out a little theory.
"Don't think I'll be getting any of that." Jack kicked aimlessly at the pile, and grinned when the Doctor caught the reference.
"How about you buy me that drink instead," he answered quietly, matching Jack's grin.