BP burrows out of sight after eating 2 rat pups

I'm about to move my yearling male bp from rat pups to weanlings, and fed him 2 pups in succession last night to make for a shade over 15% body weight (last feeding was 5 days ago. He weighs about 350 grams, and is probably a bit underweight due to a finicky feeding pattern this past winter (he's been regularly hitting feeders hard for about a month now).

He took his time taking the second pup, as if pondering the task ahead (this is the first time I've fed him two pups at once). Soon after eating the second, he crawled into his humid hide, and burrowed himself completely under the cypress mulch and sphagnum moss I have in there, to the point of total invisibility. I've never seen him do this before.

I'm wondering if taking the larger than usual meal made him feel instinctually more vulnerable. That's my thought. Anyone else seen something like this?