[ Given enough time to settle in, set up the lab (moon-side, thanks to fun with shadows), and at least enjoy a night or two of having a bed to himself, it's inevitable that Lambert will find a guest in his cabin.
It's well after dark, but not so late that Lambert isn't still up, poking about at his alchemy work, that he may sense another person suddenly arrive. Snow and pine in the air are enough to let him know who and that is definitely isn't Strange, since, scent aside, Childermass is the one who tends to show up silently, without bumbling or announcing himself. ]
early on moon-time
It's well after dark, but not so late that Lambert isn't still up, poking about at his alchemy work, that he may sense another person suddenly arrive. Snow and pine in the air are enough to let him know who and that is definitely isn't Strange, since, scent aside, Childermass is the one who tends to show up silently, without bumbling or announcing himself. ]