[DeX-kun]

Originally Posted by Tak

Sheryl was constantly being checked upon, but Grace kept on switching samples until it proved too late for Sheryl to reverse the outcome. She was interned in the hospital, she was constantly getting her check-ups, but with Grace being the meddlesome factor, it was impossible for Sheryl to know.

Moreover, after being told of her condition, Sheryl did immediately get a checkup. Or rather, Klan done it for her. Unfortunately for Sheryl, Klan's conclusion was the same as Grace. Then she later got her final check up from Luca, which of course, could not prevent her eventual death other than informing that she is temporarily capable of matching a fraction of Ranka's power. So at the end, yes, Sheryl thought she was taken care of, she had no reason to doubt Grace until her interactions with Ranka became fishy (call that a woman's instinct), and she confronted Grace only to find out about her imminent death. She was placed in a situation that was beyond her control, but that did not matter, because with whatever power she could muster, she lived her fullest using that power.

- Tak

Interesting, now that you put it that way, I guess that both Sheryl and Ranka have more in common than I originally thought.