The folks in the car had decided all hope was lost and they weren't living in a country run by woke liberal monsters, and they weren't giving antifa the satisfaction of taking them out.... They decided to off themselves, and right after dude killed everybody including his son, and before he commited himself; the calvary rolled in.
I know it was supposed to be a message to never give up hope. It just came across as pure bliss for people who are into schadenfaude.