There's a reason that every rescue course and CG rescue swimmers always approach victims from behind. Drowning people will take you down with them.
I took a risk once of letting a panicked diver climb all over me. I just grabbed his LPI, mashed the button, and he instantly relaxed as soon as he was lifted out of the water.
Had I not been able to reach his LPI from his thrashing (and he was thrashing), and he smacked my reg out of my mouth, I could always descend and switch to my pony.