[in an Outdoors Theatre, in 1955]
Young Doc: All you got to do is drive directly toward that screen accelerating up to 88 miles an hour.
Marty McFly: Wait a minute, Doc. It I go driving straight towards that screen, I'm gonna crash into those Indians.
Young Doc: Marty, you're not thinking fourth dimensionally. You'll soon enough be transferred back into 1885, and those Indians won't even be there.