Random "rescue me" spawns

[Talia]

How does the despawn timer on these work? I've tried a few when I've seen them, but the camp either despawned while I was fighting the mobs, or while I was picking the lock on the chest. Are they set on a timer that isn't affected by the player, or do they start to tick down when someone interacts with them? I actually saw one spawn right near my house last night, and before I could run over and whack the bejesus out of the mobs, it disappeared.