4: Hope the RNG is on your side, and be too stubborn to quit. It took me another 10 runs (thank goodness for having the familiar and not having mall-sold the gg tokens recently), but I was finally able to unlock ice beam in the ticket booth. While I understood the mechanics, I was running into the problems like 3 missile doors on the first round, and other basic "RNG hates you" randomization that were just making the runs non-viable for anything but tickets.