Since they went to all that trouble to switch it, I really should have swallowed that broth,

This line struck me as an elegant reminder to show that Maomao does long for a different life, or in this case, ending it all.

Or am I reading into this line wrong? She does seem to have a masochistic streak when it comes to poisons.

She obviously doesn't enjoy her situation, previously she's had thoughts on the line of giving up the dream of another life. She seems to have somewhat settled in her role, but she also hints that what lies beyond eventual release from the harem is the tough life of the red light districts.

She hasn't struck me as suicidal or even depressed, but I guess anyone can feel the allure of such thoughts at times.

No she just gets off testing poison on herself and feels exhilaration from the poisoned state.

She's basically a drug addict. Not because she has to but because she wants to.

She's a mad scientist and in a later chapter she even says that she wants to die by poisoning if her death gets decided by higher ups at some point. But she dismisses the discussion by saying she doesn't intend to die because iirc there is too much she still has to learn (mad scientist speaking).

in need of romance?
uncommon, sad, sweet