While initially Sally surely was aware of Magnar's plan, and approved it, it doesn't seem that she made any move to get close to the MC.
She constantly bitched him.
If she has a hidden agenda in her becoming first friendly, then flirty with the MC is more likely she is using him now that she discovered that he is a better student than she is.
It seems unlikely that she is operating like a sort of Mata Hari (OMG does this name even ring a bell for youngster out there?
) at the secret service of Magnar.
