I don't think the FL is infertile, so why would the mistress order to kill all the doctors if they don't shut up?
I don't think that either, but I figured she ment to kill then to not tell anyone that she was looking at the results
Either the fl is infertile, or she manipulated the results to make the mistress tthink that she is... But the point is, since the mistress couldn't be among the candidates to become the emperor's official wife (due to her low status) and since she obviously didn't want the emperor to have a child with another woman, she forced the doctors in charge of the test to use it to secretly find and choose an infertile woman for the queen position, instead of actually removing the infertile candidates like the test had officially intended. The reason she needs to get rid of the docs now is because the emperor's subordinates can't find out about this, since they'd overtly want the emperor to choose an official wife that *could*, actually, give him heirs...and not deliberately choose one that couldn't, all just to please a "pesky" mistress...
That's why she was chosen very smart, however you don't know the tricks up her sleeves.
But now I'm curious, the the previous life, her sister was chosen, so this must have happened then as well. So her sister was also infertile? Man that sucks, maybe there is a reason obviously, you can't be infertile for no reason???