crab, yes, where the scenario fits the checklist drill, it must be followed. But I agree that once in a blue moon there may be a scenario not previously thought of, not in the RFM and not in the EOPs and then yes, you are allowed to make it up as you go along.
This has happened a few times on our fleet due to the technical complexity of the 225 and the limited number of failure considered in the FMEA and hence in the RFM. In some cases it was handled very well, but in other cases very badly, which just goes to show that the more comprehensive the EOPs and SOPs are, the better.
You have to bear in mind that you military chappies were born with Raybans already attached, a square jaw and steely blue eyes with no sense of fear and cold live-or-die logic circuits for a brain. However us civilian chappies are less blessed, we fly along thinking about the necessary trip to Sainsburys to pick up toilet roll and milk on the way back home after the trip, rather than who we are going to shoot down next.
Horses for courses, we need SOPs, you don't need SOPs to shoot to kill, just an itchy trigger finger.....