Ah I understand what you're saying.
Maybe he added a second layer of glove afterwards rather than removing the bloody ones?
But as others have said, I don't think anyone is suggesting there weren't any instances of blood in the house outside the two bedrooms.
Although -- unlike footprints, there is no reason he would have needed to touch anything with his hands once he left the crime scene rooms. Even the sliding door could have been left open so he could exit without touching anything. Or there might have been a few dabs or drops of blood here and there but not enough for the house to be labelled bloody all over. MOO
Your post made me think again about the tight timeline. The mention of the sliding door --
4 am, X receives her DD food.
4 am, BK's Elantra is moving in and around 1122 King.
4 am, sliding door is shut
4:1, 2, 3 am to.... X might bring the food upstairs, go into her bedroom, eat.
4:04 am, the Elantra is parked
4:06ish to maybe 410ish, a masked intruder enters through the sliding door, proceeds directly to the third floor.
4:07ish to 4:09ish, X may return to the kitchen with her DD bag, slider is open. Odd. She shuts it, goes back to Ethan and says that someone is there...
Masked Intruder realizes other people are awake. Perhaps he heard DM, perhaps he heard X. Confronted or otherwise, he eliminates the two potential witnesses, exits past DM's door and moves toward the kitchen where he finds the sliding door he'd left open, closed.
(If K is the source of 'there's somebody here/there" perhaps she was very awake at 4 am, intending to climb into her own bed. Perhaps Murphy was responding to an unseen threat. Not playing but in distress, easy to confuse from a floor below. Perhaps K looked out her balcony door and saw a vehicle park where no one need park, perhaps she saw a figure approach the house from behind. Perhaps she crated Murphy, slipped over to M's room to tell her somebody was there... and that's how they came to be together in one room/bed when the masked intruder overpowered them.)
As for the latent print outside DM's room, perhaps that was the first
footprint that wasn't wholly obscured by blood and additional imprint detail was made visible upon further testing. Its location outside DM's door corroborates her story and helps confirm the timing of events.
I do wonder if he'd been in the house prior. Dry run. Stealth mode. Got a feel for the lay of the land, especially that one step down.
I look forward to forever forgetting his name.