THE MINES

You'd reach DOOR 186 of The Mines, only 14 DOORS Left and these hellish caverns will be over, only for most likely more places like this up ahead.

THE GENERATOR GATE SEWER ROOM

As you'd open the DOOR, the ground would somewhat shake with a flicker, though it wouldn't be Rush, instead, you'd begin to hear loud banging and growling from inside a pretty-Large Pipe going across the celling, eventually, A panel falling off of it, Figure soon following down and landing into the Room, roaring loudly before it looked around, trying to feel for it's surrounding's to see if it recognised this room, a Gate would be seen at the end of the room leading to the next one, it seems like you'll need to find a Generator and enter all the fuses to power the Gate for this one.