Mission: Impossible - Rogue Nation2015

Benji Dunn:
Well, how long will it take to free swim from the intake to the service hatch?

Ilsa Faust:
Two minutes, with the current at full power.

Benji Dunn:
Then you just have to hold your breath for two minutes.

Ethan Hunt:
What about installing the security profile?

Benji Dunn:
Well, that's gonna be, like, a minute, tops.

Ethan Hunt:
So I have to hold my breath for *three* minutes.

Benji Dunn:
[cavalierly] You can do that.

Ilsa Faust:
What I think you're overlooking is the physical exertion. The more you exert yourself, the faster you consume oxygen.

Benji Dunn:
Don't worry about him, all right? All he has to do is install the fake profile before I get to the gait analysis. You said it yourself, it's the only way. [chuckles] That doesn't sound "impossible".