Eh, this was a tough field. Two women who were definitely on track to make the final, and one (Polina) who has a good chance of making the final (plus former GPF and world medalist Satoko, even though she is coming back from injury). It may have been closer if she had rotated the lutz and combo in the short, and Mirai didn't skate perfectly in the long either. While I'm still not convinced of the merit of using the triple axel in the sp, the worst scenario for Mirai would be for her to be falling on the axel/getting downgrades rather than just an under in the lp, and to let it affect the landing and rotation of her other jumps. She seems to be holding up after the mental game of not landing the axel perfectly in the LP very well so far...
I also think that Mirai is so used to technical panels dinging her jumps at this point that maybe it's hard for her to tell sometimes if the closer ones will be given credit, and doesn't want to raise her expectations too much (aka, like at NHK last year, I think that I caught her saying "I wonder why.." at her score). Better that she keeps expectations low and is pleasantly surprised at getting credit for her jumps, I think that she had a similar reaction (being pleasantly surprised) at her Japan Open score, as she had gotten pretty low scores the last two times she was there. I know people keep going on about Skate Canada and the strict panel there, but the people like Jackie Wong who were calling those skaters' jumps in real time were able to spot the unders (though it is frustrating how much a tech panel can control the destiny of these placements, aka, still not sure how Elena at that one grand prix got credit for her combination in the short..). The commentators for nbc, cbc, and Eurosport (though they're often so wrong about spotting people's unders anyway that I don't think they really count) noted how much cleaner Mirai's jumps looked in her LP here.
I also appreciate that she is well trained enough that she is getting better at improvising the layout of her lp when things don't go her way, instead of falling apart (aka, changing her ending LP triple loop at Rostelecom to a triple loop double toe double toe/changing to a double axel double toe double loop to avoid zayaking later in the program at NHK).