Poor wee moose

I was called for as a mouse had been spotted at the front door of the building. On arrival I found this poor wee mouse in the last throws of life breathing heavily and not aware where it was nor able to move. I was pretty sure it had eaten poison and that was causing the symptoms. I managed to pick it up gently onto some cardboard packing and remove it from the door. Rather than throwing it away as instructed, I found a concealed part of the garden with a thick push and left the poor thing there in the safe knowledge that no carion would swoop down and eat it. Should have I put it out of it's misery? Probably yes but I couldn't do it.