Nah there’s already been hints to her selfishness. As soon as she denied phineas the right to choose what he wanted to do to his own body, she was in the wrong. At the end of the day, she chose her own feelings instead of phineas. Phineas wanted to do it, but because of her own trauma or pride as a doctor, she said no. And even shamed the mc AFTER it worked. Saying “if it didn’t work you’d be kicked out.” No. If it didn’t work, she’d be like HERSELF- who couldn’t do shit to save him and then he’d die like he would have. She was ready to let phineas die by giving him those leaves to make it painless. There’s no “she probably” assumption that she’s good, she is what she shows herself as. And until she actually shows such assumptions that she’s good- then she’s currently a selfish person that cares about her own decisions than her own patient. A doctor shouldn’t let personal feelings interfere with their job. That’s why a ton of irl doctors can’t work surgeries on people they know.
Also phineas is relying on someone she doesn’t know cause she couldn’t do crap for him either except accept his dying before he was even dead. No one is quick to judge when she displayed herself in that way and didn’t explain herself either. She did that shit too many times and she also didn’t apologize for pushing her. Let’s stop trying to make selfish people look good based on possible “if” scenarios that haven’t actually been confirmed over actions that she actually chose to do and words she chose to say.

I like Mia, she a complex person. She’s probabaly jealous of how Ml treats pereshati but she still makes her medicine that phineas prescribed. She wants phineas to have a painlesss death and she knows from experience that there is no cure all so to have their hopes to be on this hypothesis from an outsider seems more like her uncle being a lab rat then anything else.
Plus we all forget that we are getting more of the perspective of pereshati then Mia. Any times we could’ve gotten a look of how she truly feels we don’t. Because each time it’s a wide shot of her silhouette against the background. It’s been a long time since she’s seen some of her family members and from that time someone she holds dear pushes her to the ground, coldly rejects her, and shuts the door in her face. And now she realized her uncle is going to die and instead of relying on her/family he’s relying on someone she doesn’t know and doesn’t have the professional background/knowledge to really help out. I also feel like she could’ve pushed pereshati away in the end to protect her from Phineas’s blood. It could’ve been because of the shackles too but we don’t know because like phineas we couldn’t hear the surroundings.
Some of you guys are two quick to judge. For me I hope they turn Mia into an ally with complicated feelings but doesn’t blame the MC. I would hate to see that she chooses the victim mentality and blames all of the bad experiences of hers that has happened as being pereshatis fault.