Thank you for the feedback! For level 4: The button opens the door only for 2 seconds after being pressed. This means you have to make sure that you press it at the end of lets say A’s turn and be ready to instantly walk through in B’s turn… Pressing it too early will make the 2 second timer run out before you can enter with B. And trying to walk in with C after pressing the button with A won’t work since skipping B’s turn will cost you 5 seconds aswell…
It is a bit hard to explain through text but hope that helps!