Bucky MCU / Clint 616
It was a very fortunate thing that Clint had enough instinct and insight not to ask 'are you okay?' because that would've just made things worse. And it was probably pretty obvious that he wasn't okay because right now he wasn't trying to hide it. He was upset, and thought he was alone, so he wasn't going stone-faced or stoic.
That said, it was damn near impossible to sneak up on Bucky Barnes, so as soon as he heard the other man he straightened up, his expression gone and replaced with neutrality. He couldn't really explain why seeing Clint made him feel a little more at ease. Probably because he wasn't Steve or Stark. He was someone Bucky didn't have history or baggage with. That in of itself was a relief.
"Of all the back alleys in Starklandia, you had to walk into mine." It was a weak joke, but it was still one that rolled off the tongue as he attempted to be normal for a hot minute.