Look around for a weapon to threaten them with - it's the only way out!

You see an ornamental bowie knife on the wall - clearly a trophy of some sort, you grab it and test the edge - sharpish enough to be a threat.

You look out of the window, hoping they separate, you see them unloading then you hear the front door slam and the car engine start. You look as it pulls away, you have no idea who's driving, but you see an empty passenger seat.

Then you hear footsteps on the stairs, you move to the door and as it swings open in a panic you extent the knife and make the threat;

'Don't speak, don't scream and don't argue'