Why didn't the lawyer shoot him in the head and vital body until the perp was dead? Now the stupid shmuck will have to sue himself.
Probably he didn't see the entire incident, and had to react too quickly to determine if there was a wider attack.
Keeping the attacker alive (but immobile), allows an interrogation to find out if he was sent by a larger militia group (and serves as evidence of a violation of the cease-fire).