I seem to be the only person I know who sees the humour in novels by Kevin Brooks, and even I found it hard to see the funny side of this one. It's even more quirky than usual - passes way beyond the point of disturbing. The hero wakes up trapped in an underground bunker and "things" - people food and other stuff(!) arrives in the lift. They are watched by cctv cameras presumably for the enjoyment of their captor and there seems to be no escape. The book is a diary of what happened written by one of the captives in the bunker.. Exactly as it says on the tin.
If you're familiar the "Saw" movies it's like those but without a happy ending!