My very first multi-engine lesson, after we'd flown about 45 minutes and I get acquainted with the Apache, the instructor slapped the right mixture back to simulate an engine failure. After trimming and establishing proper SE flight, he returned the mixture control to cruise setting, and the engine failed to start. The cable had broken at the carb linkage. So my first ME lesion included a real SE approach and landing, which seriously wasn't all that difficult on a 5000' runway. We were based at a 2200' runway though, and that would have been interesting with one feathered.
I've also had the mixture control come apart at the panel. Engine died. I just crammed everything forward back in place and held it there while student flew back to base. New mixture control cable installed.