Think back, what was the likelihood of mistaking one of his movements for an attack?
What is the likelihood of you actually stabbing him?
Your accessibility( time it would take) to get to the weapon?
Would the weapon cause your dad grave danger, did it just look like it could ( a couple of stitches vs. We don't know if he'll make it)?

This all says whether you were able to unknowingly take precautions to prevent harm. Your pdoc needs to know that stuff.

To prevent it from becoming worse
Are you willing to restart your meds?
Do you have a safe person or place?
Likelihood of this type of thing happening again before next time?