I read the guide on multisources and it made no sense, heres how I've got mine set up
123
456
789
123-567-9 will all blow you up, 8 will open the door, then 4 cna be pressed, messing it all up.
I need to make 4 not be pressed untill 8 is activated, then when 8 and 4 have been pressed, it opens the door.