(This is to show the basic idea, obviously building on the tower more would be a good idea.) As I'm sure most of you know, you can walljump by pressing up against a wall. By spamming up while between two walls that are 2-3 blocks apart (or more, but you need a bit of left and right action for that), you can ascend while walljumping back and forth between them. By adding the trap blocks it makes it only possible for your team to walljump up, and having the extra trap block on door level makes it easier to walljump into the door. It also appears that walljumping with 3 spaces between the walls is fastest.