How to be invincible:
step1: find a way out of the map, whether it be a hole or a wall you can climb over. just get to the slate.
step2: obtain a wrentch. this may be tricky, as sometimes it is in adminonly rooms and sometimes its just lying around. some servers have a /wrentch command.
step3: make a spambrick and event it to change your datablock to an invincible playertype.
to build, either have the host's trust or make a big zonebrick over the build.
to moonwalk, hold the "walk" key and the "backwards" key. you will go backwards with the forwards animation.