Maybe she berated him before he took the camera out and he decided to bring it out for evidence or proof that she is unstable or just angry.
Accident's happen.. I get that all of us can be angry, at least initially, but 99 percent of mature adults will understand the situation,calm down and move on.
I seen something similar in NY on 90. Traffic, chick jumps out and starts freaking on some older lady, I mean bat shit crazy, all because she almost rear ended her. She was flipping out. Scarred the shit out if me. Lol