He frequently attempts to achieve permanent, or at the very least temporary, residence within Tenpenny Tower. Unfortunately, the affluent residents of Tenpenny Tower are prejudiced against ghouls, considering them to be worthless and unpleasant "zombies".
Depending on how the player handles the quest Tenpenny Tower, he may reside there.
If you get Roy in to the tower peacefully, he will eventually kill everyone inside (besides the ghouls). This includes Allistair Tenpenny, Herbert Dashwood and the security personnel.
If the player completes the Tenpenny Tower quest before doing The Power of the Atom, and chooses to destroy Megaton in the latter, Roy will have a short discussion with Burke on Tenpenny's balcony. After expressing shock at Burke's ability to infiltrate the tower, he warms up considerably when he learns of Burke's plan to blow up "that smoothskin shithole".
Upon letting the feral ghouls into the Tower, it is possible that Roy will be killed by security personnel.
Even by asking Roy about the human residents, then finding the bodies in the storage room, then asking Roy about the killings, you will still lose Karma if you execute him for it.