He's locking the other door.
4 seconds sound clip from the The Tingler (1959) movie soundboard.
You can hear this line at 00:36:10 in the Blu-ray version of the movie.
Quote context
[...]
- He's leaving us out of something.
- But what? There's nothing in the lab.
- It's not a drug. It's an acid.
- Locked. He never did that before.
- He's locking the other door.
- He's saying something to the tape recorder.
- Average injection: 50 micro-milligrams. Fifty. I'm making it 100 micro-milligrams in solution.
- Warren wanted to do this. Let's hope he's accomplishing something important.
[...]