Ah! Had no idea.
Instant Dramatica -- a very useful tool -- is a way of porting the actual theory over into practical terms. It's not part of the theory.
I would argue that it isn't directly advocating for a specific moment in the story, but a way to encapsulate in an outline an example of when the Main Character (in the MC Throughline) comes to term with the fact that their method of going about things isn't working.
I don't think you are going to find a related story point for the Mirror.
In Hamlet (I believe) this moment does not exist. The Solution is adopted without reflexion. So, not only is there no Crisis, there is no Mirror either.
Likewise, imagine a character with a purpose (I want to be team captain) and a motivation (I hate being low status). At a certain point, these two things could come into conflict -- "In my desired to be team captain, I have started picking on the scrawny kid -- but that just makes me a jerk". This feels a lot like Casablanca's "what have I become?" but isn't necessarily connected to the midpoint.
You are correct in saying that it may have more to do with Cost, Dividends, Requirements but I would take it a step further. Many other things could be combined to give your character a moment of reflexion. How you combine story points to create this moment is part of Storytelling and not directly associated with the storyform, or any specific story point.
Another thought: in the middle of Lives of Others the MC has a moment where his behavior changes outwardly for the first time (with the kid in the elevator). I can see an argument that this is a moment of self-reflection like the mirror Bell talks about. However, I would not argue that it motivates the character in any way. It doesn't propel him through the midpoint.
In this way, it probably violates Bell's ideas, but only if you look closely.
Nevertheless, we cannot disregard the affect it has on the audience: they are probably excited to see the changed (I was) and it motivated me to keep watching with interest.
To this end, I encourage you to dive in and explore the idea of mirrors and propulsion, but encourage you to divorce it from two ideas:
• Don't look for a specific story point, but rather, look to see how several story points have been synthesized for the specific story you are looking at.
• Once you have explored the middle of stories, broaden out to other parts of the story. In general, things get more difficult for the duration of any story. The characters have to constantly dig in their heels and wonder if the are strong enough to do it -- or, perhaps, know they too weak , but are the only chance to prevent a horrible outcome -- or both. There is no reason on the surface for this to only happen in the middle.