Trial of the Sekhemas last boss stuck behind closed door

I have no clue how to upload a picture here, but I saved one if you're interested in it.

During the scorpions burrowing phase he went up from the sand inside the first room you're able to enter after killing him, and he's been stuck there ever since. Unable to shoot through walls, aoe right outside the door, use pets etc. Can't think of anything else to try.