Triage is just to deal with limited resources, essentially it divides the applicants into 'walking', 'dead' and 'care', and the fewer resources you have the more people will get sorted into the 'dead' category even if they still have a pulse when you see them. The 'care' category will still get unique personalized care otherwise you might as well sort them into the 'dead' category on the spot.

How much training does someone need before they become a clear net positive for the patient?

The ICU staff would not even allow the doctors to mess with their setup because it is critical and it is their responsibility until some either dies or is discharged from the ICU and allowed to move back to a normal ward.

Think 'airline pilot' not 'assembly line worker'.

If I had to choose between an uncontrolled emergency landing, and an emergency landing done by a volunteer who did two days of training, I'd choose the volunteer every time. I understand that the volunteer does not have the training to fly or land safely and that becoming an airline pilot takes a lot of training, but that doesn't matter if there's no pilot available.

If 20% of patients die with trained ICU staff, 90% die with no ICU staff, and 70% die with a trained volunteer, and you have no more ICU staff, then the volunteer is a net positive and the volunteer has left a lot of dead people. The question is not whether the volunteer is even anywhere close to a trained professional in effectiveness, it's whether the volunteer is better than sticking a red or black tag on someone's bed and leaving them to die.