The hand twisted a dial, and Reio was suddenly filled with lust, insatiable lust. He wanted to reach out and fuck them all, to reduce himself to a rutting animal. But then the hand twisted another dial, and lust smoothly turned into fear. He was completely at the mercy of his captors, and they clearly didn't care for him more than the white mice he had seen in the adjoining room. A twist, and everything was cold and clear again.
Emotion consists of both arousal and a cognitive component.
I can change both, and turn any emotion into anything else. I can even turn them off completely, although you will lack motivation to do anything. The voice moved, and this time he saw its source. It was a small man in surgical gown, with large shining eyes reminding Reio of a Disney rabbit. Reio couldn't care less.