|The following is based on Fallout: Brotherhood of Steel and has not been confirmed by canon sources.|
Follow the vault girl through the ruins and remember to stay close to her. You're slowly losing health from the gaping hole that was once your left arm. Note that your actions are limited - you cannot run, jump, or use two-handed weapons.”— Quest description
After being thrown into the abyss by Attis, the Initiate is woken up by Mary. Follow her through the maze of ruins. Because of their injuries, the Initiate is incredibly slow and steadily losing health. Use stimpaks to prevent the player character's health from reaching 0. Mary takes off, but if she gets too far ahead, she waits for the Initiate. As if the wound isn't enough to slow everything down, radscorpions and baby deathclaws attack from every angle. Smash them using one-handed weapons and continue to follow Mary until the last door. As Mary urges the other side to open it, the Initiate faints and wakes up in the Facilities' medical bay.
The Ruins One have some valuable loot; it can be picked up later during a second run (Find Ring).