The next day (or later that same day. I don't know. After sunrise. Whatever), Ma Scully takes William out in his stroller, almost getting both of them killed when she steps into the street without looking both ways first. She finally does manage to get the two of them back to the apartment without incident, but the instant she opens the door, Ma Scully gets grabbed by Buck. She squeals. Personally, after everything that's ever happened in that apartment, I don't know why anyone goes inside without first drawing his or her gun.
Scully's car pulls up outside. She sits in the driver's seat for a second and looks tired and guilty before getting out of the car and heading into the building. She's almost to her own front door before she notices that it's slightly ajar. Scully pushes the door in, calling for her mother. Ma Scully is then thrown out of the bedroom and against the wall of the hallway. Scully races inside, pulling her gun. "He wants to kill the baby!" Ma Scully hollers. Scully runs to William's room. Wait, William has a room? Two months ago he was sleeping in the living room with total strangers. Anyway, Scully races into her son's room, where Buck immediately grabs her and knocks the gun out of her hands. She promptly socks him in the jaw. They fight. Scully gets smashed against the wall, and Buck eventually throws her into the hallway and locks her out. Scully leaps off the carpet and starts banging on the door. "I'll kill you! I'll kill you if you touch my baby!" she screams. "Dana," Ma Scully offers hesitantly from behind her. Scully turns around to see her mother gingerly holding out a handgun. Scully grabs it, and shoots in William's door, then plugs Buck, who's in the midst of raising a pillow over William -- either to smother him, or to make him as comfy as possible, I don't know. Buck drops to the ground with a groan. Scully looks sorry she ever had a baby.
Doggett and Moronica come rushing into the apartment, stopping briefly to make sure that Ma Scully isn't about to drop dead. How did they know to come over? Did Moronica have a feeling? Did Scully call them? We're never to know. At any rate, Scully comes wandering into the living room, clutching the baby and absently rubbing his head. "What the hell happened here?" Doggett wonders, looking concerned. Scully just looks at Moronica and says that she needs her to take William and Ma Scully. "Can you do that, [Moronica]?" Scully asks. Moronica can, of course. Doggett looks progressively more concerned. Moronica takes the baby, reaches out to Ma Scully, and escorts them both from the apartment. Behind Scully, Buck makes a faint strangled sound. "Who is that?" Doggett asks. "Somebody here?" He stares at Scully and her bloodied forehead. She doesn't say anything.