Well, I'm of the opinion that if your enemies are stuck in a small cubicle and won't come out until something pokes them, that's just waiting to be exploited. Whether by an explosive near the door, or otherwise. So, not so fine.
Here's a quick battle save, turn 6, all Reptoids still stuck in the kitchens. Note that one of the kitchens has only one Reptoid in there, so it can't be blocking itself from moving.
Of course, if the mansion is full of enemies, some of them never leaving the kitchen might even be interesting - a cooking contest, doing drugs, or whatever else they might be up to there.
But if
all of the enemies are stuck there, it's a different matter. AFAIK, this Reptoid Assassination mission is the only mission that uses the mansion map and has so few enemies.