if the requirement is for hypothermia kit, then they are probably thinking about something called a Palmer Furnace.
similar to a Scout Fire, where the need is to build a small fire and avoid detection, the Palmer Furnace is for rapid body warming.
to do this, sit down cross-legged with a blanket (reflective Space Blanket works good) around your shoulders and set a lit candle on the ground between your legs. you can completely close off the space and a couple of tea-light candles will warm you in a hurry.
here's a pic of a Scout Fire.
the Palmer Furnace is done similarly but with a candle, or originally, a carbide miner's lamp.
I think it goes without saying that since you are setting a fire between your legs, inside what is essentially your shelter, for safety you should remain very cautious. I suspect that is why they recommend you use the UCO lantern instead of an open flame...