When I built that command block elevator, the tutorial said that it was survival-friendly. But only in bedrock edition, because I tried it in java but the slabs just appear which is supposed to happen, but instead of lifting the player up, it suffocates the player. Clip coming out June 4-5. It works fine when the player is going down in the elevator.

========EDIT========

Clips released June 5, 2021 at 3:28 P.M.

Up function clip (Kills player) here  Down function clip (Does not kill player) here

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