The master computer needs some sort of 'door'

[davidjoffe]

i.e. your path to the teleporter on last level when you put the AV disk into the master computer must be blocked by default, and then open up when putting the disk in, otherwise you can just skip this step, silly, in which case you didn't save the world from SystemD

[davidjoffe]

DONE BUT NEEDS SPRITEWORK just copied access door sprite and changed color :/