After reading grimoire and a little help from Google I feel like I may have found something interesting but I can't figure out how to trigger it. The grimoire talks about thanatonauts (look it up). So immediately after reading the grimoire, I decided to let myself die and see what happened. When you die, change the camera angle and you will notice that the mission waypoint changes to Rasputins room or whatever that room is called in the beginning of the mission to the left. I also figured out that if you go to the end of the mission and kill the enemies then run back and kill yourself in the water, just before entering the beginning hallway, then you re spawn in Rasputins room. There are places for enemies to spawn but I don't know how to trigger the mission. There is also the possibility that spawning in Rasputins room could just be a glitch. Edit 1: To re spawn inside the room, make sure you kill yourself on the other side of the water upon running back (meaning just jump to the corner that's to the left on the other side).