The keys I still carry don't fit anything anymore

Woke up at 4 a.m. doing the rounds in my head again — checking cells that were torn down years ago. I used to think the silence on my shift was proof I was doing something right. Now I reckon it was just the sound of not listening hard enough. I've started writing letters to men I used to guard, unsent, just to hear myself say the things I should've said through the bars.