Dude:
Have you ever noticed that you can just ignore where the levers are and just identify which way the aeroplane has yawed, then maybe that phenonen will give you a clue to which engine failed?
Flamboyant use of mixtures, fuel shutoff levers and ignition switches are just asking for trouble, when reducing a throttle will give you a loss of power for the purpose of training.
I recall almost crashing many years ago on a check ride in a DC3. There were two of us being checked and I was in the jump seat for the first take off. The Chief pilot whipped the right engine mixture to idle cut off just as we were airborne with insufficient runway ahead to land and the gear still in transit.
The mixture lever broke right off the pedestal and we damn near lost a perfectly servicable airplane, thankfully we were light and the thing flew.
Chuck