I note some of the replies with a mixture of amusement and amazement. I am a multi-engine instructor with over 7000 instructional hours, of which close to 2000 are on twin piston aeroplanes. Now the very last thing I want to do is sound as though I know it all or make as though I am better than everybody out there. However, there were some comments that made the hairs on the back of my neck rise.
First were the ones from BigEndBob and let_me_fly who related the stories of when a student switched off the wrong mags. They do not say at what altitude this happened, but my questions are these: - Whatever happened to touch drills? How come a student is allowed (taught?) to switch magnetos off? Again, without knowing the exact circumstances, whatever happened to the rules about not shutting an engine down for practice below 3000 feet agl?
Next are the gems from kabz and GT who talk about retarding mixtures to simulate an engine failure. What, pray, is the problem with merely retarding the throttle to idle? The asymmetry is just as obvious and the technique is exactly the same. Difference is that it is all being done with two operating engines (albeit one of them is at idle). In all the time I have been instructing on twins the schools I have worked for NEVER used the mixture to simulate an engine failure.
On a lighter note, and to answer the original question from B2N2, I had a student some years back who applied the wrong rudder while practising an EFATO (fortunately at altitude). The aircraft behaved as expected and rolled very quickly through 360 degrees, by which time I had managed to close the other throttle. On remonstrating with him for applying the wrong rudder he passed the blame on to me for failing the wrong engine.