I'm sure an 86 year old woman is going to jump out of her bed and go all Jackie Chan on you.
No, but how is he going to get the knife away from her, in bed or otherwise, without getting cut? I don't think Denny was saying he's concerned she's going to flip over his head and stab him, but you aren't going to get the knife away without getting cut.
I don't think we have enough details on this story to really make a comment about whether these officers did the right thing. It looks bad because she's 86 years old, but an officer getting cut up trying to disarm her is worse than her getting the taser, if that's even the way it really happened. But that's just my .