Assuming you have invincibility on and one hit kills the boss should be no problem.
When you get to the big orange room (Hotline) you gotta pull the string/cord that is dangling in front of the large pit. When you pull it, it will go purple. Pull it two more times to be teleported to a hotel. There is a bell on the desk of this hotel that will open one of three doors passed this bell. You want to get the key from 226 and enter the door near where you first entered the hotel. Pull the cord in there 3 times, you will teleport back to Hotline and a bridge will have formed. Go answer the phone, complete a course, speak to Pope (in the board room) and achievement popped.
you can fast travel there quite easily. need more help?https://guides.gamepressure.com/control/guide.asp?ID=51240