Well, obviously, he has to take her out first, but even before she gave him the knife, that shouldn't be much of an issue; she left him one hand and both feet, she's standing, like, right on top of him, he's a trained male martial artist, she's (AFAWK) a normal human, and she's batshit nuts. One good punch to the temple while she's swooning in the wrong direction and he's gold.
Clearly, his wife's incompetence is wearing off on him.