I'v emuch enjoyed the textual ping pong and so cannot resist joining in - a little.
With a thousand hours (all of which I have paid for!) I have had 2 partial engine failures.
The first was climbing out and the options looked pretty limited. Thankfully as the nose went down to 'best glide' speed the fuel supply refilled the carb and with a series of climbs and glides I got to 1500 ft and this allowed a sensible circuit to be flown. Mechanical fuel pump unable to pull fuel from a low tank.
In that case 'instinct' kicked in and I simply flew the aircraft.
The second time a cylinder head on the Gipsy cracked and meant the engine started to shake the aircraft to bits. In this case I did suffer from a ' is this really happening', 'surely not' period when to be honest I was well behind the aircraft. Even after sorting myself out and finding a power setting which almost maintained height I found myself in a state of disbelief. My immaculately maintained engine could not be doing this etc...
But to be fair it kept going long enough to take me out of the mountains and to a large military runway (gently descending all the way).
But Guppy's comments about disbelief and lack of preparededness do really strike a chord with me.
That incident really did change my mental model - to the point that when my ANR headset battery gave out recently I already had a field, high key and circuit, carb heat and fuel selection sorted out before I noticed what had caused the big increase in noise.....