trigger-happy

The man in charge saw Gilgamesh on the alarm screens and got trigger-happy.

At least, he was reasonably sure that none of Klem Zareff's trigger-happy mercenaries would shoot him down coming in.

Suppose he broke surface right in front of a flock of trigger-happy Enforcers?

However, a couple of trigger-happy vedettes let off their carbines at them, yelled, "The Rebs are coming!"

Uncle John provided our hunting excitement by turning out to be one of the trigger-happy types.