Pulling that trigger is definitely not cowardly, it's hard to pull that trigger.
Take it from an old trigger puller. Right, Dad?
One can endorse the act or condemn it, it really doesn't matter-- but it was in no way cowardly, given that the man was certain to be known and recognized and apprehended. He may well have anticipated the death penalty and yet submitted quietly. That is not the action of a coward.
"Give me liberty or give me death."
"I regret that I have but one life to give for my country."
Cowards?