How does this script cause players to fall through?

So I made a block with a timer and once the timer goes off the block moves up like a timed elevator. The purpose is for players to be able to enter the map on it. But once the Block starts to move, the players automatically fall through. Can Collide is checked aswell so I don't know what the problem is.

speed = 1300


wait(10)
local startingPos = game.Workspace.Elevator.Position
        local endingPos = game.Workspace.Elevator.Position + Vector3.new(0,30,0)
        local elevator = game.Workspace.Elevator

        for ratio = 0,speed,5 do
            local newPosition = startingPos:lerp(endingPos, ratio/speed)
            elevator.Position = newPosition
            wait()
        end

        wait(10)

        local startingPos = game.Workspace.Elevator.Position
        local endingPos = game.Workspace.Elevator.Position + Vector3.new(0,-30,0)
        local elevator = game.Workspace.Elevator

        for ratio = 0,speed,5 do
            local newPosition = startingPos:lerp(endingPos, ratio/speed)
            elevator.Position = newPosition
            wait()
        end