The distraction from the shouting pedestrians toward the police officers I think effected how things overall panned out.
I think Chauvin became emotionally resistant to taking his knee off of Floyd by all the shouting and suggestions by those people shouting at him..
Kind of like " I'm the police officer here, you dont tell me what to do or how to do my job. "
Anger and frustration can build up in situations like this even for cops while on duty.
The video of Chauvin with his knee still on Floyd's neck even though the pedestrians could see Floyd was out cold, is a indication that Chauvin wasn't completely aware of what was going on.