Bran saw the doors at the same time Lotte did, but he held himself back from racing towards them - partly because he didn't want to look too desperate, but mostly because of the fact that Ella's damned vines were still in their way. He regarded them with a mixture of wariness and curiosity, as though he didn't know what they could do or that they were spurred on by her fear. As far as everyone present was concerned, he'd only heard about what Ella could do; he'd never seen it for himself.
He simply watched as she backed towards the door, knowing that she was afraid but keeping his expression appropriately confused when the vines suddenly shot upwards.
Then she was gone, apparently spooked by something, but frankly he didn't really care what. All that mattered was the vines disappeared a few minutes after she left, and they could finally leave. Shaking his head, Bran slipped off the edge of the stage, headed towards the doors - freedom. If Lotte didn't say anything, then Ella wouldn't know his apartment number yet.