Fast way to cook steel-cut oats when no microwave is available
My low-effort steel cut is to set the bowl of steel-cut and water in a steamer and let it go about 20 minutes (or longer) - unlike (my experience of) cooking them in a pot, there's no stirring, boilovers, or other drama. IME the drama fully applies in the microwave and no time is saved by it. But you are not going to cook them in 10 minutes time (2 minutes active work, yes, 10 minutes time, no.) On the other hand, I don't see why you'd be cooking for 40 minutes in any case.

Edit: I begin to suspect from the comments that @Jim is not familiar with the concept of steaming. So, steaming, the short explanation: A small amount of water in a large enough pot. A rack set on the bottom of the pot to elevate the bowl. A bowl contianing food (in this case, steel cut oats and water in a ratio of 1:2) is set on the rack above the water. The lid is put on the pot, the water is boiled, the steam in the pot cooks the food. 

Other method I haven't used in years but which worked then and should work now, is to put the oats and boiling water into a wide-mouthed thermos flask the night before. Given that the main reason I haven't done it in years was that I dropped and broke the glass on my wide mouth thermos flask, I would suggest a stainless-steel version rather than a glass version (my stainless steel narrow-mouthed flask is old and dented and still going strong, more than 3 decades after it was new. But I wouldn't want to put anything other than a liquid in it due to the size of the mouth.)