Stupid decision (spoilers)
He didn’t have to lose his job by shooting the guy’s hand.
He heard the guy admit to the crime - “I’ll never tell you where I left her”
That statement is enough to get the DA to press charges. The main character could’ve just waited, tell his superiors everything, and then they’ll coerce the inmate to tell.
What’s also stupid is that he tells the grieving father about the daughter’s location. But the grieving father is now going to jail, so he can’t bury her. So what is the point?