He means business

This morning, I noticed a man standing on the roof of one of the six- or seven-storey buildings which our thirteenth-floor office overlooks. He was peering over the edge and moving in an aimless sort of a way. After a bit, he disappeared off around a corner and out of sight, and I realised that at no point had it occurred to me that he was there for anything other than savoury, non-suicidal reasons. I thought about it a bit longer and decided that this was because he had a pencil behind his ear.  Killing oneself doesn’t somehow seem compatible with having a pencil behind the ear.