The pressure outside is three and a half tons per square inch.
5 seconds sound clip from the Titanic (1997) movie soundboard.
You can hear this line at 00:03:59 in the Blu-ray version of the movie.
Quote context
[...]
- Seeing her coming out of the darkness like a ghost ship still gets me every time.
- You are so full of shit, boss.
- Dive 6. Here we are again on the deck of Titanic. Two and a half miles down. 3821 meters.
- The pressure outside is three and a half tons per square inch.
- These windows are 9 inches thick and if they go, it's sayonara in two microseconds.
- All right, enough of that bullshit.
- Just put her down on the roof of the officers' quarters like yesterday.
- Mir 2, we're landing right over the Grand Staircase.
[...]