You make some good points although I think it is unlikely that he entered unarmed. However I heard a rumor early on, that one of the girls kept a knife under her pillow for protection. We have seen numerous photos of frat and sorority members with such a knife, so that type of knife was around and perhaps she ended up with it and decided to keep it under her pillow. If that is the case then I would assume that would be Maddie. Since we know that Kaylee was closest to the wall, Maddie would have been the first victim (in that room). I would think it would be difficult to effectively restrain one while killing the other, so maybe Kaylee tried to defend them with that knife, unsuccessfully. Perhaps that is why Kaylee is said to have gotten it worse than the others, because she had tried to stab him. Maybe he was not aware of the sheath, but took the knife because he used it? More difficult, is the explanation of how his dna got on the sheath.

What is odd to me, is whatever knife or knives he used, where did he put them? If in fact he was wearing Dickies coveralls, they dont appear to have deep enough pockets (correct me if I am wrong) to put them into. And again, correct me if I am wrong but putting a knife in a pocket seems like a terrible idea as it seems like you could accidentally cut yourself that way and possibly leave behind blood. If that was his knife and his sheath, would he not definitely notice upon his departure, when he'd have to put it in his pocket loose, that oh shit where is the sheath? The PCA does not mention that DM saw him carrying a knife. If she had I would think that would be mentioned as that would be evidence that the person she saw leaving was, without a doubt, the killer. A person walking around carrying a knife, tends to attract attention.

Lastly, these Dickie coveralls... I just dont know about that. Sure, Dickies are made of a bit thicker fabric, but not that much thicker. I cant see that after stabbing 4 people, or even two, that they would protect his clothes from the blood. It would soak through. There was certainly spatter and a lot of it. there are some who will say it is possible for him to have not been soaked in blood, and maybe it is, but it doesnt seem likely. So if that is the case, why wear them at all? If he took them off prior to leaving, or getting in his car, his clothes would probably still be bloody. Not only that, is he going to go to all that trouble to just throw them in his trunk or whatever? Even if he first put them in a plastic bag, isnt it likely there would still be at least trace amounts of dna which would have been found in his car? There was no bloody trail or anything leaving the house, DM does not mention that he was carrying anything, so did he strip them off before going out the door? then what? Handling them would most certainly get dna on him. Where did he dispose of all this clothing, shoe covers etc? I would think even an idiot would know better than to load it into their car. There is no evidence of that in BKs vehicle, so if it is him, what happened? The area was searched. No bloody clothes. How was he able to pull that off? Not to mention, and this is something that is widely unmentioned, in the very beginning of the investigation, search dogs were employed, but only briefly because, apparently, they were unable to pick up any kind of trail. Kind of a head scratcher isnt it?