Not surprising at all. Ask any lawyer in a situation where a car accident occurs on a crowded street, and there aren't but two witnesses who actually saw it and can be contacted and questioned. Odds are, one's going to swear the light was red and the other's going to swear the light was green, each will be as honest as the day is long and speaking in absolutely good faith, each will be describing it exactly as he or she remembers it, and that's about size of it. It's just the way of the world. Only one thing can be the truth, yet each witness is being absolutely truthful -- about his or her recollection of it, not necessarily what actually happened.

In the Las Vegas shooting, you had the shooter (who's not saying too much or answering questions right now), a couple of security guards, one or two maintenance guys, some Las Vegas cops, each member of an an entire SWAT team, hotel management, and the front desk staff involved. Each of them will have a unique individual perspective, they will each remember things differently. Each will have been, at the time, observing from a different vantage point in the hotel: some on the 32nd floor, some in the lobby. The only way we could know as close to the whole truth as is relevant is if somebody had been standing right next to the shooter at the time he started shooting, and lived to tell the tale.
But it didn't work out that way, and this investigation is going to be relying very heavily on security video, and reconciling the various individual perspectives and versions of the story.
In the Las Vegas shooting, you had the shooter (who's not saying too much or answering questions right now), a couple of security guards, one or two maintenance guys, some Las Vegas cops, each member of an an entire SWAT team, hotel management, and the front desk staff involved. Each of them will have a unique individual perspective, they will each remember things differently. Each will have been, at the time, observing from a different vantage point in the hotel: some on the 32nd floor, some in the lobby. The only way we could know as close to the whole truth as is relevant is if somebody had been standing right next to the shooter at the time he started shooting, and lived to tell the tale.
But it didn't work out that way, and this investigation is going to be relying very heavily on security video, and reconciling the various individual perspectives and versions of the story.