Let's imagine we put a ball inside a box such that it doesn't touch its walls, and suddenly drop the box. Because the two objects fall at the same rate of acceleration, the ball will stay at the same distance from the walls of the box while on free fall. Correct?
Now, let's imagine the same scenario but with a really long box; one that extends from a few hundred meters off the surface of the Earth all the way to outer space where the force of gravity is much weaker. Let's imagine we put the ball inside the box, near the wall of the outer space side.
What would happen when we drop the box? The Earth surface side of the box will tend to fall at a much faster acceleration than the outer space side of the box. Will the outer space side of the box be pulled down by the Earth surface side causing the outer space side to fall faster than it normally would? Then, does that mean the ball would collide with the outer space side's wall?