Minecraft wiki entry for Minecart, associated text: Players can exit the minecart by pressing sneak, however, if there is only one block of headroom above the cart, the player takes 1 of suffocation damage. When a minecart is exited, it searches for an adjacent or diagonal 2×2×3 area to put the player 1.5 blocks away from the cart. If none are available, the player is deposited directly above the minecart. Consequently, the player falls inside the minecart.