I find it particularly clever. What they are telling is that this is body for a human to occupy. Sensation and sound of breathing is simulated for him.

He's still in bit of a shock of waking up not in his own body. I guess pulling was instinctive reaction upon seeing it and finding a (painless) hole in the side of his face.

I thought that also, but look at his body, it's machine to the bone so I was thinking where is the place for the human to occupy? I was thinking, maybe he just "thinks" that he is breathing because he was a human and wakes up to be like this.

What's that with the downvotes? A robot doesn't need oxygen to fuel chemical reactions.