Especially since the OP gave no indication of what to look for. If the question was "What should the C have in this clip?", maybe it's different. Instead, we are being asked to watch all ten players at once, a task that basketball officials are only asked to do on the Internet.

1st view I'm looking for a travel on the post player who scores. I still think he was legal.

2nd view I'm still looking at the travel and notice white on the ground after the score. Thought maybe red #20 grabbed or pushed him.

3rd view I see a clear punch and FTF.

Would I catch this real time? I would hope so. I think the T should have been watching 20 since he left his area and was going very aggressively toward the paint where 4 players on white are getting in position to rebound. And I think the C had a good look and should have seen it. Though I can certainly see how it was missed in real time.

And maybe its just me but I really don't like how the C moves. After the made basket on the other end at the beginning of the video look how he opens his shoulders up to the baseline and then back pedals for a few steps. This may have something to do with why he never really gets in good position to step down as the C on the play in question.

Then after the basket he opens up his shoulders too early going the other way. He's never really square with the plays on the court and IMO this may be why he didnt get a good look. Perhpaps he misses this even if he's in perfect position but I don't like the way he moves regardless and its something I would point out when I'm asked to observe other officials.

Don't Be Asleep When The Ball Is Dead ...
 

Here, in two person Connecticut, we are always reminded that, as the trail, we should be watching for such activity immediately after a made basket. I wonder if some previous situation led to the sucker punch to the gut?

It's a pretty safe bet that the kid who threw the punch in this video is a "troublemaker" that my crew and I would have identified much earlier in the game. THAT guy gets my attention whenever and wherever he is on the floor. I'd like to think that I would not miss this if I were the C - however, I can't see thru players backs...These are the kinds of players and plays that can get you fired! I would DEFINITELY be watching him

btw...it took me 4 viewings before I saw what needed to seen. Good officials don't just officiate in a "vacuum" - they have a feel for the game and don't get surprised.