Murder or Euthanasia?

Warning - contains gross imagery.

It all started last night. Sue was having trouble sleeping due to sinus drainage so she went downstairs to sleep on the couch. However, she had trouble sleeping due to some uninvited visitors that were making strange noises in the laundry room at first, and later beside the TV. I thought I would set a trap for the visitors to ensure there would be no more strange noises keeping people awake tonight. The first time I went to check the trap the peanut butter was all gone, the visitors had won round one. The next time I set 2 traps near the site of the earlier defeat. Later in the afternoon, we were in the kitchen when I heard a snap. I went to look at the traps. One trap had killed one visitor, and the other trap had also killed a visitor. This was no surprise that is the function of the traps. However, this time there was an unexpected twist. One of the cute little mice had its head in the trap, but its legs were still moving. I had seconds to react. What should I do? Should I leave and let the mouse die on its own? Should I somehow help it? What if I don't react fast enough and he escapes? What is the most humane thing to do at this point? I decided to end the suffering of the mouse and stomped on its head about 7-8 times. But how hard do you stomp on a little mouse that is suffering to end its misery without needlessly making a mess in the laundry room? I tried to find the perfect amount of force to kill it as quick as possible without the mess part. I could not believe that it was still moving at stomp number 5. I especially couldn't believe it when I picked up the trap and saw the gory remains of the mouse. When we got back from Awana another mouse was in the trap and this time he was lucky enough to die before we got to the trap. It was lucky for me also. One murder is enough for one day.