I will repeat that I think that Aziz is guilty of not getting consent, but there is plenty of nuance in her verbatim statements. If she meant "no" then just saying "no" would communicate that more clearly.

I don’t think I’m ready to do this, I really don’t think I’m going to do this.

"Think" implies uncertainty. If you I ask you if you left the stove on and you say "I don't think so." that isn't the same as saying "no." It leaves room open for doubt.

The phrase "not ready" suggests that you could be ready at a later time. In some contexts, it even means that you will be ready at a later time. "I'm not ready to go to the store." is very different than saying "I'm NOT going to the store."

As for the whole second half of the sentence that you've singled out: "I really don’t think I’m going to do this." This sounds to me like the kind of thing you say when you're working up the courage to skydive or bungee jump and trying to talk yourself out of or into something. It's really still not a clear "Hell No" as you say. "Hell no" IS a hell no, though, of course, and would have cleared everything up!

But, in any case, she says that after saying "I really don't think I'm going to do this" Aziz did stop the current effort and they put their clothes back on.

Moreover, I attempted to call attention to the ambiguous subject of the sentence: "this." Does this mean PIV sex in front of a mirror, or does it mean any sexual act at all? Keep in mind that many other sexual acts had already taken place. It's not crazy that he might have thought she meant that specific sexual act, since, from her point of view, she was fine with oral stuff.

Again, I don't mean to victim blame or take the focus off of Aziz. But it isn't as simple as you say either. We have a serious problem with the nature of consent discussions in most sexual encounters that people need to get better about resolving. "Yes means yes" and "no means no" would at least be a good start: Aziz should have gotten a clear "yes" and she could've given a clearer "no to everything sexual."