You don't want to crash into some tree that once existed in the past.
— Dr. Emmett Brown (Christopher Lloyd)
4 seconds sound clip from the Back to the Future Part III movie soundboard.
You can hear this line at 00:16:56.733 in the DVD version of the movie.
Quote context
[...]
- Your future clothes are packed.
- Just in case, fresh batteries for your walkie-talkies.
- Oh! What about that floating device?
- You know, Doc, it's gonna be a hell of a long walk back to Hill Valley from here.
- You don't want to crash into some tree that once existed in the past.
- This was all completely open country, so you'll have plenty of run out space when you arrive.
- Remember, where you're going, there are no roads.
- There's a small cave over there which will be a perfect place to hide the time vehicle.
- Well, the new time circuit control tubes are warmed up.
[...]