All right. Thoughts.
Sevar is correct that she could've suicided to Osirion - something that Aspexia and Abrogail themselves should have thought of, especially after that being a hypothesis for the Asmodia incident. They must have actually started trusting Carissa Sevar on some level, not to think of that; or simply failed to imagine themselves sufficiently well into Carissa Sevar's place, trying to ravel these problems with INT 24. It is, in fact, not her or Abrogail's primary stat, neither of them have more than a couple of Wishes on it, and Carissa is now as enhanced as it's possible to be in Golarion.
Aspexia could have maybe nabbed her back with Miracle, but it would have needed to wait until the next dawn, and they would have needed to decide to move the project or Carissa's portion of it permanently out of the nonintervention region - though they would have, for that. But she also had geas earrings in her possession - and as something of an unfired plot device, at that.
Verdict: Yes, Sevar could have made her way to Osirion, at INT 24, if she acted before anyone read her thoughts. Gorthoklek, who is smarter than that according to Detect Thoughts, of course failed to warn them because nobody requested Gorthoklek to think about it.