Zane had passed out almost immediately after he lied down on his bed. Olivia had done the same as she curled up next to him. Though Zane's body no longer required sleep to function, he had been awake for a very long time, well over a week straight.
After all, he had been the one to keep watch over the girls every night. But that was no longer required now that they had the bunker. For the time being, the Undead had no means of penetrating into the bunker, meaning they could sleep easily every night without fear of an attack.
This mentality of relief, combined with the state of intoxication that Zane ended up with after celebrating with the girls, compelled Zane to sleep, and sleep he did. When Elena stumbled into the young man's new quarters, she gazed at the sight of him, and Olivia entangled together.