He doesn't need to know how to sign to be able to tell she's afraid of him. For now he reasons that it's a good thing. Even if she doesn't recognise him, the Soldier's reputation is a double-edged sword he's contended with for many decades. Rather she not fuck with him than launch straight into mind games.

He doesn't have much exposure to signing beyond military commands so he isn't able to understand everything she's trying to tell him. He is, however, very comfortable with silence. He doesn't respond, the rusted old gears in his mind groaning as they turn while he figures out what he should do next. She looks genuinely confused, but he doesn't trust her. Should he test her? Try to find some identification? Murder her on the front lawn?

Clenching his teeth, he decides against the latter. He should at least murder her quietly in the basement. No witnesses. No reconditioning program.

He leaves her standing there while he retreats back into the house. He should turn on the radio, check the pager thing. See if anyone's mentioned anything. While he closes the door, he doesn't lock it. Although hopefully she doesn't go wandering around too much if she decides to come back in... in a previous fit of paranoia he's booby trapped the back door and the basement entrance, various other doors and windows.