It was necessary to maintain the illusion for your crew.

3 seconds sound clip from the The Hunt for Red October movie soundboard.

You can hear this line at 01:54:06.926 in the Blu-ray version of the movie.

Quote context

[...]

- Well, the captain seems to think you're some sort of cowboy.

(In Russian) You talk Russian. -A little. It's good to know what the enemy thinks, isn't it? -It is.

- I doubt you'd remember, but we met once at the consulate in Leningrad. Along with your wife. I'm very sorry.

- What gives you the right to fire on my ship?

- Your signal said nothing of a torpedo.

- It was necessary to maintain the illusion for your crew.

- My crew are being rescued, yes?

- As we speak.

- You sent the signal.

- That's correct, sir.

- Then how did you know our reactor accident was false?

- Well, that was a guess, but it seemed logical.

- Very well. I present you the ballistic missile submarine Red October.

[...]