@Kaarme
I'm not really an expert with the story, but here's my takes.
1. Mao mao doesn't know what's the true position of Jinshi and she also oblivious of his feeling towards mao mao.
Mao Mao still think that she will be executed if she make any mistakes, and she still didn't believe Jinshi will help her/ have any capability to help her.
Her line of reasoning could me something along "Jinshi position might be high, but surely someone is higher than him? If this someone higher than him suspect mao mao of something, could/will Jinshi really do anything?" (refer to ch 15, page 15).
The fact that Jinshi know what mao mao are capable of (in term of medicine/poison) is actually make it even worse (from her standpoint of view).
2. This might a bit far fetched, because it doesn't explained very well in novel (up to vol 2 at least), but Mao Mao tends to avoid unnecessary confrontation (except when it's about someone being harmed), especially with her father.
There is one chapter that talked about how her father forbade her from touching corpses, because he afraid mao mao will take it to another level of creepiness.
She know that she won't drop to that level, but she still abide with her father's warning.