These were very small bedrooms IMO, with very little floor space. I think, in the final analysis, the crime scene will bear this out: MM had next to no reaction time. KG, more. Not enough to defend herself but enough that BK had to improvise, resulting in the same fatal wounding, just more haphazard in delivery.
Similarly, I think EC had next to no time to react, at most sitting up. Much has been said of XK's defensive wounds, and I won't in any way minimize the horror of what she witnessed and experienced. She was perhaps the most awake of the roommates. But BK had the advantages of ambush, kbar and size. It's quite possible XK was attacked twice -- near fatal injuries, followed by EC being killed, then fully fatal injuries. Doubtful she was able to engage in any real hand to hand combat. Small room. Mostly bed. BK's wingspan -- 6'+. Add a Kbar and there's virtually no place in a small room he can't reach. IMO XK's injuries will reveal the brutality of the Kbar's design and the savagery with which BK yielded it, against a victim who had exactly nowhere to move. At most, her hands flew up or out, to protect herself, or to existing wounds, or to try to grab the knife. Any and all of which would have resulted in additional wounds, to her hands, and IMO a bloodletting only imagined in movies. Arterial spray, blood spatter from the knife itself, much of which BK may have been surprisingly clear of. Behind the knife, above all four victims.
Chaotic but BK remained in control of the knife. Utterly defenseless victims, which was his intention.
IMO it took him longer to park, enter, exit and drive away than the killing took. Hardly longer than had he used a gun.
JMO