“Gunman can claim the spray made his trigger finger involuntarily jerk.”
I think there’s a good chance that’s what happened.
1. Improper finger placement on the trigger.
2. Involuntary reaction to the spray, perhaps the trigger was set light and basically he had an accidental discharge.
Might get him down to manslaughter or similar charge. Anything seen about the “second gun” that was in an early report?