Obviously I didn't write the movie to say for certain, but I would bet a lot of money that it wasn't Cap hammering the shield. For one...do you even hammer vibranium? Another, I can't see his shield making that noise. And third, it makes no sense. I'm 99% sure it is a callback to Tony Stark, the person this movie was ultimately about. Of course everyone else got various levels of treatment, with Cap being almost equal to Tony, but after seeing the movie it is clear that this entire decade was Tony's story. It started and ended with him. They didn't even have a post-credits teaser because they wanted to honor his story, with no distractions. The noise was, in my opinion, clearly the sound of him hammering his original armor, the thing that literally started all of these events in motion.Oh duh. That makes sense.
Still think it was Cap hammering the shield. They spent the whole movie looking back. An allusion to the future would be more fitting for the MCU. Wouldnt be mad if it was Tony from IM1 though.
Sure, I could be wrong. But I doubt it. I know you allowed for the possibility of it being Tony, but just making my case for why I think it isn't your first choice. Hopefully they'll say officially at some point just so we can be sure.
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