I've personally had what's known as the "sleeper hold" used on me.
Within seconds, you start to black out.
Within minutes, your brain starves for oxygen.
It's not even a "violent" tactic....you just press the arteries on either side of the neck.
It can be done with just one arm if the arm is used to make a v-shaped "vise grip" on the victim's neck. [that's what I got]
You have no chance to struggle or squirm, it affects you -that- fast.
I was lucky.
I think Terri wasn't.
I also think he thought he'd held her "long enough" since she went into cardiac arrest.
Done "properly" it leaves no evidence of external or internal damage.
There's a line in a Jethro Tull song;
"They know how to hurt and leave no mark".
Indeed.
Me too. I verify exactly what you said. The "knock out" only becomes known to you as you wake up from it.
It's a great way to end a fight.