Like I said, in the hands of a competent and current pilot a light twin does offer a technical safety benefit over a single. However, what I've seen about the statistics is that that technical safety benefit is negated by having twice the number of bits that can go wrong, and by pilots going on more dangerous missions. At night, in fog/IMC and over water for example - something that only very brave SEP pilots would do.
And let me offer up another story for comparison. One of my pilot friends had a recent fATPL and was due his MEP checkride. For preparation he booked a sim session with an instructor and I was invited to sit RHS just for fun. The request he had to the instructor was an IFR flight ending in a few different approaches plus some failures. The usual workout.
After one particular missed approach, climbing away at full power, still in IMC, the instructor failed one of the engines. Three seconds later we were inverted in the field, dead, and the instructor stopped the simulator. The look in my friends eyes was something to behold.
Now I appreciate that an FNPT-II (or whatever it was) certified simulator is still not moving and does not give you the seat-of-the-pants yaw response that a real twin would give in case of an engine failure. That may offer a partial explanation why my friend didn't react instantly the way he should. But it still shows that in a twin things can go from good to hell in a very short period of time. In a single, at the very least, the aircraft would not have inverted itself in zero time flat, giving you far more (though still limited) time to figure out what to do and where to (crash) land it.
Edited: I guess the point I'm trying to make all along is that twins are not automatically and inherently twice as safe as singles - something your missus seems to believe. Yes, twins offer more safety and more options in case of an engine failure but the downside is that it requires more training, more currency and more money to be a competent enough pilot to realize these safety benefits.
Last edited by BackPacker; 18th Oct 2011 at 14:16.