It’s also possible to use the ‘all ghosts bug’ in e1m8 (haven’t watched yet to see if it’s used here - the runner may have judged it more time consuming to set up than it would save). A single projectile making too many collision checks can overwrite some memory and disable all collisions for the map. Then you’re free to void walk to the exit. It’s only useful on that one map because of its unique death exit that doesn’t require a further collision check.