He's only suffering in his mind. Nothing is hurting him.
5 seconds sound clip from the The Tingler (1959) movie soundboard.
You can hear this line at 00:40:11 in the Blu-ray version of the movie.
Quote context
[...]
- The room is closing in on me. You've got to make it stop. The walls! The walls!
- Break the door. Break the lock. He may be suffering. That drug may be hurting him.
- He's only suffering in his mind. Nothing is hurting him.
- I got to get out of here! No breath! No air! I can't breathe!
- The window. It won't open! It's locked. Barred! Somebody's got to help me!
- We gotta get in there. Isn't there another key?
[...]