Car has done it about 3 times since I've owned it. This was the worst. Clutch in and holding and coming to a quick stop the car shut off. The bad thing was I was right in the middle of a right hand turn and about went off the other side of the road (no power steering/brakes). Scary moment.
I've had it happen to me a time or two ad you're right it's a scary moment. Last time it happened to me I cleaned the battery terminals really well and the connections is what I think was causing it. I haven't had an issue since. Good luck man and stay safe out there!
With the engine warm and idling, unplug the IAC valve and observe what happens.
If the engine RPM drops below 500 or the engine stalls the minimum idle air is set too low. To fix this, loosen the throttle-stop set screw and adjust the throttle stop until the engine idle is stable and at about 500-550RPM. When the IAC is plugged back in the engine RPM should rise to its normal hot-idle level.
You might also want to verify that the EGR valve is closing completely (i.e. the plunger is free of carbon and not binding or hanging up.) EGR flow at idle is basically a vacuum leak and that can definitely cause stalling.
I've also had this happen to me just after I bought my 2002 GT (~2003). I braked coming up to an intersection and the car just died. Hasn't done it since.
Mine has died on me a couple time while braking and turning as well. Every book I looked at said there is no idle adjustment. When I unplug my IAC it dies immediately, does everyone's car continue to idle with the IAC unplugged? I thought it was normal for it to die when unplugged.