I'm not a pro either but I do have a good understanding of predatory animals. Your observations are I feel closer to mine than any thus far. Mentioning territoriality is an important observation.I am not a professional trainer, but I trained a few dogs. One of those (mine) was really "mean" and hurt to tame. We had to find an agreement on that LOL...he does what I ask, but I leave him alone if he wants to be left alone. I have never had to do with lions and not sure I wanna try either.
First of all, place. All animal, pets or wild, are very territorial. That doesn't mean only they protect they territory, but they also feel confortable in it. A lion out of its place will be in the first place nervous even tho you can't tell by just looking at it. Notice how quickly he runs out when the door is opened, no need to force it that way. The lion knows that out of there he will be out of that foreign place and hopes to go back to his territory.
I don't know how far are dogs and lions behaviours. Dogs have two ways of being hostile, attacking and defending. Fortunately I have had to deal only with defensive ones and that means they actually they don't mean to bite you unless you force them. That lion dind't show neither one kind of aggression even tho it might look like it. Glad it was stopped, but had it gone along with what he was doing I doubt he would have hurt the woman (well, intentionally. Lion doesn't know his size and weight are enough to kill her). Putting the woman down is sign of dominance and I think the lione wanted to prove he was dominant.
Remember it was not his place so he needed to make that place his. His trainers were no threat to him and the photographer was clam and quiet. The woman was moving slowly back and forth and the lion might have seen a threat for the territorial ownership.
Of course I am no pro at all in this subject so I might be completely wrong.
We talked about our own private space in terms of self defense. There are those who we would let in and those who we would prefer not to. Predatory animals, especially large ones I would imagine would feel the same. The woman probably wasn't "properly introduced" to the lion in the first place. Just showed up and started shooting pictures. Flashes of bright light directly in it's eyes and a strange (smelling) human(s) moving around and getting awfully close to it's comfort zone... definitely a recipe for disaster.
I don't get casual with a large dog until it has a scent of familiarity with me. Meaning that if the owner is about then I take pains to ensure that the owner introduces me to the dog and the dog sees that I am not a threat to it's "pack".
Thus could've also been a contributing factor with this animal.
Watching a special with a supermodel getting to know Bart the Bear (Grizzly Addams, The Bear, The Edge) was more of a behind the scenes and the handler had to be with the model closely for a period of time so that the bear was familiar with her.
Things to think about.