This is just one of the many horrors yet to be found.
There are now Slender Fortress servers that can be replayed... even though the monsters and pages, gas cans, etc. are not to be seen through relays. Want to join in a server like this? I recommend Xenogame's server that has more bosses. The easy way to get there is just click on the replay supported box in case its not on and scroll down until you see Xenogame with Slender Fortress next to it I could not find it when I typed either Xenogame or slender.
Please share so others can play, survive, run, hide, and die.