His expression twisted into one of frustration when Clarke said she needed him. That they needed each other. Frustration because she was right. Frustration because his knee-jerk reaction was to just shout 'well, too bad!' and leave. But where would he go? It was an immature, defensive reaction and it was fleeting. Something he swallowed back before really even thinking it through. Because unlike Clarke, he didn't have that sort of resolve. Bellamy had never had that sort of resolve. Not really. He committed atrocities for others, but only because he needed them. He shot Jaha because he needed his sister. He destroyed Raven's radio because he needed to stay with Octavia. He killed that guard in Mount Weather, because he needed to get his people back. He pulled that lever because he needed Clarke and he knew if she did that alone she would be lost forever.
He never could have walked away from everyone the way Clarke did. He needed them too much. That was why Clarke had been able to convince him to come back to the Dropship. And it was why he couldn't shut her down and leave her alone here. Because he needed people too much.
So he nodded silently. Because he did need her. And because he didn't trust her - not completely, anyway. He didn't trust her to not shut him out. Clarke was right - she didn't deserve his trust. Or his forgiveness. Maybe his anger, but he couldn't really even find too much of that. Not here. If they ever got back home and if she ever stuck around there, Bellamy was sure he could find plenty of fuel for his anger. This place was different, though. It made it harder to be angry when he knew she was right - they were all they had.
Bellamy sighed, the sound half irritation and half defeat, when Clarke's fingers ghosted over his knuckles. Irritation because she didn't deserve to hold so much sway over him. It wasn't fair that a barely-there touch from her quelled so much anger and bitterness. Only Octavia was supposed to have such power - because Octavia would never betray it. The defeat came because Bellamy may have wanted to hold out, to be cold, but he knew he wouldn't be able to do it.
"Together," he said gruffly, with a brief nod. Because that was really all he wanted - more than he was probably entitled to. Clarke had somehow managed to morph from an obstacle into someone he would do anything for. He found himself so devoted that Bellamy had tried to do and to be whatever Clarke needed of him. It just turned out she had only needed him as a weapon, a crutch, a tool. How was he supposed to trust that wasn't what she needed right now? Just a tool to get her through this strange place. And did it really matter if that was all she needed?
"You can pick any room you like," Bellamy said, after taking in a breath. "I haven't done much with the place..." he trailed off, not really able to even half-heartedly attempt to change the subject with small talk. He cleared his throat, "If we're going to do this..." Bellamy abruptly moved back to the issue at hand. "You can't shut me out. If you want to be like-" he stopped before he finished like we were, because he wasn't sure what that meant. "We need to be upfront with each other," was what he finished lamely.