Bucky doesn’t have a very long turn around time when it comes to adapting. It’s one of his talents. But he’s still Bucky and he’s going to want to dish it out to HYDRA.
The vault scene mashed a lot of hurt-comfort buttons. It was a pivotal moment in the Winter Soldier’s onscreen characterization, and that moment was one of confusion and disorientation, capped with screaming horror.
I’m fully convinced that Bucky was processing his flashbacks and coping (ish) with a PNES conversion disorder. For me, the seemingly childlike psychology was a transient state, not a useful representation of Bucky’s typical state of mind – or his ability to function. I’ve avoided the helpless-kitten fics and posts. I can understand where they come from, but they’re not my headcanon, not my kink, not my Bucky.
The Bucky I know would’ve stolen some nondescript clothing from a shop while everyone else was trying to figure out why the sky was falling into the Potomac. The Bucky I know had a new mission – information. The Bucky I know will have kicked so much ass before we get to Cap 3 that it makes me want to weep with joy.
I also prefer the capable post-WS Bucky. Even during his winter soldier time, I feel like – he commands a strike team, he plans the missions, he executes solo missions. Pierce turns him loose after Natasha and Cap and says he has ten hours. That’s a pretty big window for him to work in – he must have had a snack and a bottle of water. If they had him on such a tight leash that he could not feed himself, he would have had a much shorter window to execute that order, I would think.
I think the @thedevilsbaklava has it right. I think the bankvault scene is a huge anomaly for the character but it is so powerfully acted by Stan, Redford, Grillo, and others that it pushes a lot of buttons for us. I don’t think that child-like desperation, that seeking of answers – is at all typical for the character. But because it is all we the audience see, it colors our perspective a lot.
Yes, they do a job on him, but his subjective time as Winter Soldier is what? Maybe a couple of years. Five years tops. He was a highly capable, functional adult when they got their hands on him. He’s not like comic!Natasha, whose brainwashing and training started when she was a child. He’s not even like comic!Bucky who started black ops as a teen. MCU!Bucky has a lot more to fall back on in terms of life experience outside the military.