Luffy was starting to fight the admiral who caused this mess when Sanji came upon Zoro's sorry shackled form. Barely functional shackles he noted. Zoro could have probably escaped if he wasn't looking so defeated by guilt.
Che! He thought he deserved this. As punishment.
Hardly surprising, he did call the marimo an idiot daily for good reason after all.
"Do you really need me to get you out of this?"
Zoro's eyes flicked up at him.
"Leave. I'm not one of you. I gave up the right when I betrayed the crew."
"LIKE HELL I'D GIVE UP MY NAKAMA!" Luffy's scream echoed loudly in the background in response to something the admiral was saying. Sanji smirked at the timely response and gestured toward their captain helplessly. Zoro showed no sign of being swayed, as if he hadn't even heard it.
"You didn't have a choice right? You're not the first one that betrayed the crew to misguidedly protect us."
"It's different. The girls, they hated it the whole way. I…I enjoyed it."
"They made you enjoy it." Sanji corrected with a hiss. Zoro shook his head in disgust.
"I should be stronger than that! What good am I if I can't control myself?"
Sanji moved close, sliding his hand behind Zoro's ear. The bastard had a point but he was too glad to see him and he'd be damned he was going to let him go. (Even if the captain hadn't given the direct order to bring him back.)
"I'm sure we can find a use for you until you feel you've been punished enough." Sanji smirked before pulling Zoro into a deep kiss.
"ZORO IS FAMILY! YOU DON'T TOUCH FAMILY!"
The cook grimaced. Zoro grinned, snapping his bonds as Luffy thoroughly ruined the mood.