Oh, a mysterious snore is much better than a cave-in. Come to think of it, they likely did have an outing like that. The last few years of them trying to make it work, they made a point of getting everyone together for special family events... Really, the question answered itself after the divorce. She probably hadn't gotten any sleep, and after too many years she couldn't take it anymore.

But distracting himself with memories like that won't keep him from noticing the snore, or realizing there's probably some kind of hibernating bear in the tunnels ahead.

He slows his approach, keeping the flashlight more steadily directed at the ground a ways ahead of him, so the flickering's less likely to grab the attention of anything - or anyone - ahead.