Your first responsibility is to yourself, then your family. If you feel you have any responsibility for the public, they are a distant third. Legally you have no duty to act, so whether you do or not is a personal decision based on the circumstances. The circumstances you described, I would continue on and contact the police as soon as possible. I would probably have stopped before entering the melee, and turned around if possible.
The OP said this made him think about deploying a firearm while on his motorcycle in full riding gear, and this is a reasonable thing to think about in general. A coworker of mine carries his firearm in a tank bag on his motorcycle, so that he can easily access from a riding position should it become necessary. If you were wearing riding gloves that prohibited firearms use, you could simply pull it off and throw it away as part of your draw. I cannot see any reason in real life to shoot while actually operating the motorcycle. If you're still riding, focus on exiting the killzone.
"I don't make jokes. I just watch the government and report the facts." -Will Rogers