Hiro has lived in a lot of places where mice and even rats were a problem. He used to get rid of them using traps. But then he had a run of bad luck with the things. He would hear a trap snap shut in the middle of the night, and then instead of silence he would hear pitiable squeaking and thrashing, whacking noises as the stricken rodent tried to drag itself back to safety with a trap snapped over some part of its anatomy, usually its head. When you have gotten up at three in the morning to find a live mouse on your kitchen counter leaving a contrail of brain tissue across the formica, it is hard to get back to sleep, and so he prefers to set out poison now.