Well on the bright side with most house layouts the bedrooms tend to be clustered so as long as they're sleeping in different bedrooms (and one isn't in a master bedroom or lounge room or games room or something inconveniently on the furthest opposite end of the house) you should theoretically be able to find one in one room and find one in a neighbouring room.

_{Now having said that you do end up with houses like mine that are stupid layouts because they started out as one type of house and then haphazard diy extensions happened.}

Failing that, unless they're unconscious or otherwise crippled, I'd probably be inclined to throw a chair or something through the window, chuck the kid out after it and tell them to go out the front to mum (and make sure they go while taking a quick breath of fresh air, this is also assuming that I can see to the front and there isn't a fence/gate in the way) and then duck back in to go and find the other one.

Afterwards (having either found the second child or having had to bail out or die and probably having made my lung issues significantly worse because smoke inhalation) I would probably do all the frantic panicking I put off at the time XD

^{This reminds me, I should probably actually clear out the stuff blocking the side door (weird layout of our house means all bedrooms are conveniently right next to an external door) and see if the kids remember the fire plan (we haven't discussed it in depth for a while).}

I'm guessing this was a hard question because you mentioned genders so people hyperfocused on that? :)