I look back into the house, looking for anything that moves (such as a person that might have come through that door that opened and closed).
If there is something, and it can't see me, I stealthily walk back into the room and stab it repeatedly ["He ran into my knife, Officer, I swear! He ran into it twenty times!" or however that goes]. If it does not then crumple to the floor after being stabbed many times, or attacks me back, I take my knife and run out of the house, making sure not to touch or trip on anything in the process. Once I'm safely outside, I'll look back to see what happened to the thing. If it's coming after me, I'll keep running, continuing to make sure I don't trip or touch anything.
If there is something and it can see me, I get out of its sight. If it pursues me, I run away while making sure not to trip or touch anything.
If I see nothing moving in the house, I walk back inside, making sure not to touch anything, carefully looking for anything that wasn't there before. If I see something new that I could deem dangerous (such as a person crouching in the corner or a translucent ghost or something) I will run back outside, carefully as usual. If I see nothing, but something invisible touches me, I run back outside carefully. If I see nothing, and nothing touches me, I walk into the living room. If I then see something dangerous in there (such as a person that does not look injured), I will run back out of the house carefully. If I don't see anything dangerous in the living room, I will examine the room, making sure not to touch anything.
...<.< New rule for all of my posts: always assume that when I do something, I do it carefully, making sure not to touch or trip on anything, unless I say something to the contrary.