Quickly but unpredictably fail an engine?

[Chrixxer]

I want to practice multiengine procedures, especially "emergency" single engine operations. (I've found a $20 Duchess and a $42 Duchess; anyone know how they compare?) Ideally, I'd like to have a random engine fail randomly, but within say 10 minutes every time. It could be on take-off, it could be "en route," it could be on approach. I just don't want to wait around all day for it, but I also don't want to manually fail it myself. Trying to get as close as possible to being in the cockpit with an MEI or examiner (except they're not likely to fail my engine during the take-off roll - but I'd like to practice that!). Can that be done with X-Plane? I've seen where you can setup a MTBF for a component, but I'm a little confused as to how, or if, I can set it up the way I've described...? Thanks!