I watched the whole thing, the longer version. For most of it Trump thinks they already have an agreement. They plan to eat in the East Room and sign it after eating. But when Zelensky speaks, what he says isn't quite making sense to Trump. And vice versa (Zelensky squirrles up his face numerous times). And only after a lot of statements it seems both of them are more and more uncomfortable and starting to realize they are not actually on the same page. Then JD vance picks a fight and Trump already feeling these things (and supressing them for the sake of the deal) realizes the deal isn't happening as he envisioned and goes ahead and says what he really thinks.

I don't think any of this was planned to happen that way.