She will leave the tower if her safe in Boutique le Chic is looted, claiming it's not safe despite all the guards. If her safe is looted before she is spoken to, which triggers her to leave and wander aimlessly around the wasteland, she will only come back if Roy and his gang are killed.
If she is convinced to leave, or simply killed, house upgrades will no longer be available to buy. If this happens, the only other option is to let the ghouls invade the tower. After the invasion, Michael Masters will take over the shop, and his shop will sell the house upgrades.
"Some people don't like living in a boring old suite. Purchase a theme from me and I use all of my design abilities to set your place up in the manner you request. You can choose from the Vault, Raider, Wasteland Explorer, Science, Love Machine or Pre-War Themes."
ps3xbox360pc If she decides to leave Tenpenny Tower, she supposedly heads out to Megaton and can be found outside the main gate causing tremendous graphics lag for some reason. Scaring her away or killing her instantly removes her effect on performance. Note that if you kill her while she is at Megaton, all of the guards outside Tenpenny Tower will become hostile, regardless of whether the killing is witnessed. [verified]