It doesn't so far look like the start of an escape plan, unless there'll be some elaborate operation that supposedly must needs be carried out before the trip to Dis, proposed once Aspexia's suspicions are lulled... she doubts a traitorous Sevar would expect Aspexia to fall for that, but Aspexia will know what she's reading if that comes next.
It's - sort of an overwhelmingly tropey version of Aspexia's imagined true-loyal Sevar who found some fault in her loyalty and would lay out some much more mundane plan to correct it. Perhaps there will be some evident reason for the drama, in the next paragraphs.
Alternatively: some initial gambit of an INT 24 traitor who has read Aspexia Rugatonn about as well as she could.
It will depend on what the rest of the letter says. If this is all the plan, but for notes on corrigibility, then Aspexia would in a tropeless world consider herself reassured enough.
Aspexia turns the pages back into her vision, and reads on.