So as an experiment I dominated the Gar. Not only can you loot its head without killing it, things looked funny swimming on land as it moved and attacked. A little experiment that got eliminated soon after.
The obvious question: why? How? The more interesting question of course is: DOES it, in fact, earn XP and level up while dominated? :O
It was from Dominate Monster via console import. (a test cheat not kept) and yes it did earn experience. But as a 10hd monster it would take too long to level up.
Considering it's a GIANT Gar... was it blocked by door-awnings being too small, like with an Enlarge Person target?
I didn't play with it much and nothing indoors. But I'll guess it would be hindered. No phasing through walls.