[Paal Gulli]

"I don't recall all the details of the medical examiner's report. I do recall that it listed fentanyl and meth having been found in his blood...."

A massive, probably lethal overdose of fentanyl. And the symptoms GF displayed were textbook for near end-stage of a death from a fentanyl overdose. And the prescribed method for controlling someone in such a state so they don't further injure themselves or anyone else until medical help arrived ... was a neck restraint.

[Reily]

Except the restraining officer didn’t have a Star Trek Tricorder to do an instant blood analysis prior to applying the restraint. He just followed his training.