That is a reasonable set of circumstance in which Missy would throw a challenge to allow Baylor to continue. Sort of. But I'm guessing that neither Jac nor Keith (nor Natalie, really) are laying down at the F5 IC, and Missy can't make that decision unless she and Baylor are miles ahead of the others. Those Simmotion challenges are just a pick up your ball and start over type of thing, so no one is eliminated like in the endurance challenges.
So unless Baylor and Missy are vying for the win and are nearing the end of the challenge, odds are that she won't even have to chance to throw it to Baylor.
But it could happen, and the reasoning that either Missy or Baylor go is compelling, thanks to you and G.
Natalie won't go, Jac and Keith are at F4, and a Missy eviction isn't a surprise or a blindside in any stretch of the imagination.
So Baylor? Could it be?
(BTW, I wonder if the producers could have substituted something that Missy could compete in for a more physical F4 Immunity Challenge that might have been originally planned. It would have been a daunting logistic challenge, but they had a week or so to get it together. And I'm sure that they have contingency challenge set ups in their back pockets just in case they need them. Aren't the final ICs usually an endurance test?)