Lan couldn't say he was right when he thought that this night would be very long, because there wasn't any possibility of being wrong in the first place. It was like saying the sky was blue in the morning —it was an irrefutable fact.
He literally just closed the door and he already wanted to run away.
He played multiple scenarios in his head in which he acted different ways to see what it might lead to, but he was so worried that in each of them, something went wrong.
Taking an external look at the situation, it wasn't even that big of a deal. Especially since they didn't even have to sleep, so even the fact that there was only one bed shouldn't be a bother.
But seeing it from Lan's point of view, it was a bother ! Because it was still a closed space that they had to share for a whole night. And even if they didn't sleep, what would they do ?
Twiddle their thumbs and wait for morning ?