I predicted what happened on a flight the next day.
Sat in the back awaiting my turn with one other doing 1179 training.
Inflight shutdown of Seneca engine after failure to air-start.
The checklist ran in the usual fashion without a break after pulling the mixture. The guy upfront went straight for the wrong mags and killed the live engine!
Very interesting when several miles out over the Channel (which looking back was not very clever place to do this procedure).
Realising error he immediately switched them back on.
Very interesting flight.