That was one part of it, sure. He wasn't the type who would let anything stop him. That was all the more obvious given the kind of trouble he's gotten himself into, and more telling, too, given how close he's come to being detained for longer than a couple days, or - the worst possible - landing himself on the execution list.
So, the sun? That was the least of his concerns. He'll sleep when and where he pleased.
If Kija insisted, though— right about then did the air stir. A fair bit hotter than the room, it easily moved beneath the covers, all with a specific goal in mind: to further wake Kija by tickling him.