At the end of the day it doesn’t exactly seem like she has much of a moral quandary about the development, so why even bother with Plan A and not just kill all three of them as soon as they were brought into the hospital?
Why didn’t the Black Clover Society just kill them at the start?
The question, though, is why the hell would she go through all that trouble?
She explains that her initial plan was to try and convince them superpowers aren’t real, but finds herself forced to take fatal measures when that doesn’t work.