Chester didn't end up sleeping as much as Callum had. His wolf was happy to be out but it resulted in him feeling too restless to sleep. There wasn't much that he do though except for lazing around.
There was not much to explore and too much noise might end up waking up the little wolf who was rather happy at the current moment in time. That wasn't something he wanted to do. Because he made the promise with the other, he wasn't about to shift forms while the smaller wolf was sleeping. That wouldn't be fair.
Even though it meant that he wasn't able to do anything that he needed to, he was going to keep his promise.
He just needed to find a way to convince his body that it needed sleep more than he needed to be awake at the current moment in time. He wondered if part of it had to do with the fact that there was no natural skylight.