I am technically trained in CPR. You absolutely shouldn't rely on my CPR skills if there is another choice. Wrangling a deranged person is difficult even for people with ample training and experience (e.g. cops), let alone for flight crew with very basic training. If the person is not a danger to himself or others, there is no reason they would escalate the situation during flight.

"deranged" meaning "posing a physical threat to passengers and crew".

Stealth-jacking is certainly offensive, but it is a disgusting offense, not a threatening offense.