Assassin knows its probably fruitless to 'do' anything so he uses his vision to see if he can make out anything from the ceiling, floors and walls.
Out of Character: We are being played with but for what purpose. So far we've figured out that its not human, so its either robot or alien. I'm leaning on alien because of the technology. You're right if they wanted to kill our characters they would have done it already.
Assassin looks on as Shifter eats. He considers waiting awhile since he does not trust the situation.