I would guess the fairly large man in the front car might have been, in the very least, charged with brandishing if he reached for a weapon and exited his car weapon in hand and threatened the two behind with it, even if he didn't raise it. Most assuredly so if he trained it on them from inside his car after retreiving it from the back seat.
Although it is natural to want to get out and inspect for damage, exiting can appear confrontational and can make you vulnerable if the persons in the front car intend retaliation. Most of us have cell phones. If it were me I might just stay in the car, call police and wait for them to show up and supervise the exchange of insurance information, take pictures and make a report.