"Hmmm...."

It's hard to say what's going on in the robot's mind, with no emotions to sense to clue him in, if only vaguely. Assuming there's anything like a thought process as Merlin knows it to begin with, which is certainly a good question when it comes to such a being.

"Does something about that weigh on you mind, or are you just not the talkative type?"

Only one way to find out!