Police officers are trained to not be too 'quick on the trigger'. [=eager to fire a gun]
The timer was set to 'trigger' the bomb in exactly one hour.
The faulty wire was the 'trigger for' the explosion.
(..) She was beautiful. God, I loved her. I didn't know how to show it, that's all. I killed her, Red. I didn't pull the trigger... ...but I drove her away. That's why she died, because of me... ...the way I am. That don't make you a murderer. Bad husband, maybe. (..)1994 The Shawshank Redemption
(..) A month in the hole. That's the longest stretch I ever heard of. It's all my fault. Bullshit. You didn't pull the trigger or convict him. Are you saying Andy is innocent? I mean, for real innocent? It looks that way. Sweet Jesus. (..)1994 The Shawshank Redemption