We shall proceed as planned, and as soon as we return to 1985, we'll destroy this infernal machine.

6 seconds sound clip from the Back to the Future Part III movie soundboard.

You can hear this line at 01:11:31.755 in the DVD version of the movie.

Quote context

[...]

- I've at least got to tell her goodbye.

- Come on, Doc. Think about it. What are you gonna say to her? I've got to go back to the future? I mean, she's not gonna understand that, Doc. Hell, I'm in it with you, and I don't even understand it.

- Doc, listen. Maybe we I don't know, maybe we can just take Clara with us.

- To the future?

- As you reminded me, Marty, I'm a scientist, so I must be scientific about this.

- I cautioned you about disrupting the continuum, for your own personal benefit. Therefore, I must do no less.

- We shall proceed as planned, and as soon as we return to 1985, we'll destroy this infernal machine.

- Traveling through time has become much too painful.

(KNOCKING ON DOOR)

- It's Emmett, Clara.

- Emmett, won't you come in?

- No, I better not. I...

[...]