Once they reached the Memorial 101 was a bit taken aback when her father, presuming she had learned to handle herself in dangerous situations to have made it as far as she had, asked her to go in first to make sure the building was clear of threats. She agreed and headed in. At first glance 101 wasn't sure they'd be able to do anything in this place, most of it was in shambles. A handful of Super Mutants had seen fit to destroy almost everything in sight. She was able to take most of them by surprise, they didn't seem to be expecting any humans to be wandering around, but wished she'd had her armor repaired while they were in Rivet City when one took her by surprise. 101 managed to gain the upper hand and Moira's stimpaks came in handy so she didn't have to worry her father by hobbling out to give him the 'all clear'.
Once the team was inside everybody got very busy. James asked 101 to help check fuses and clear blockages around the building. The way he asked left 101 feeling a little hurt, but she complied. 101 was on her way back after rebooting the mainframe when she heard alarmed shouts coming from the rotunda.
Apparently the Enclave, a secretive group claiming to be the official continuation of the old government, had caught wind of Project Purity's rejuvenation and intended to take over; profiting off of the ample supply of soon-to-be clean water. Colonel Autumn had locked himself into the main control with James to "negotiate". The truth was Colonel Autumn intended to completely take over and force the science team to work under him; shooting a poor young scientist who happened to be trapped in the room with them to prove his point. James appeared to comply, saying he simply needed access to the control panel to transfer control of the facility to the Colonel. What he did instead took everyone by surprise.
It happened so quickly and with the access hatch locked no one was able to help. James overloaded the computer system and ignited the radioactive gas that had been building up in the little room, killing everyone inside. Everyone. After finally being reunited with her father, 101 could only stand by and watch him die. She felt... numb; just stood there staring at her father's corpse until Dr Li shook her harshly out of her stupor. "We have to get out of here. More will come!" 101 didn't feel like getting out of there, she felt like tearing apart that Colonel Autumn and giving her father a proper burial! A small part of her reasoned that her father would have wanted her to help the survivors, and she could always come back for him later, so she followed Dr Li to the sewer tunnels that, Dr Li claimed, would lead them to The Citadel where they would be safe.
The journey was not easy. It seemed the Enclave had learned of the tunnels as well. 101 fought off the soldiers with everything she had in her. Beyond the soldiers were a handful of ghouls. How long had it been since anybody had used these tunnels? Finally they reached the gate behind which a band of Brotherhood of Steel Knights were standing guard. 101 wasn't sure why they were allowed to pass, surely they were guarding this gate for a reason? The answer came soon enough as they emerged from the tunnels and approached the Citadel.
Dr Li walked right up to the intercom, mashed the button and yelled at someone named "Lyons" to "Open up and let us in!". 101 was fairly surprised, and mildly impressed, when the massive front gate immediately creaked open. Elder Lyons spoke with Dr Li for a few moments, wherein 101 got the impression they had known each other prior. This hunch was confirmed when Lyons said, "This must be James' daughter. She looks so much like him." 101 managed a wane smile until Dr Li turned to her asking, "Would you help us---". Something in 101 snapped. Her eyes began to fill with tears, she savagely shook her head and bolted. She didn't know where she was going, just that she had to go.