Headscratchers / Don't Breathe 2

• It's made clear that the only reason phoenix's biological parents sought her out is because she is the only compatible organ donor they can find so that they can take her heart and give it to her terminally ill mother Josephine. How exactly would that transplant work? Yes, Phoenix may be compatible in that her and Josephine share the same DNA, but Josephine is a grown woman, while Phoenix is a preteen, therefore her body is not fully grown and developed. How are they going to transfer the heart of a child into an adult? Doesn't the organ have to also match in size?
  • It doesn't exactly, just one google search told me that donor-recipient age does not generally affect transplants, but considering Pheonix is so young I can understand the skepticism. When looking for infographics online, I found that teenagers and young adults have similar heart shapes, and while Josephine isn't young, she is physically not that large of a person, I mean it's not like Phoenix is donating her heart to Dwayne The Rock Johnson. When we see an overhead shot of the two of them on the hospital beds, they aren't super far apart in size, mainly due to Josephine being ill, she is bigger but that's mainly due to her legs being longer, her chest and torso aren't significantly larger so their sternum and pericardium could be close enough in size to hold Pheonix's heart. Basically, while it seems a bit implausible, it could work.
    • Josephine is dying and they are getting a bit desperate. And these group doesn't look like the most reasonable people ever.
• Why did Jim Bob punch a hole in Jared's cheek to help him breathe rather than cut the glue between his lips with the edge of the screwdriver or, better yet, punch holes through the glue over his nostrils? Jared seems to cut it pretty easily with the broken glass.
  • Probably heat of the moment, but a better explanation could be that Jim Bob didn't want to pierce his lips on accident, or break his nostrils, which could both cause permanent damage, unlike a pierced cheek which actually heals rather quickly. Also worth mentioning is that Jared would be able to do a much less dangerous and precise cut since he would be able to feel his lips and know where to cut in order to prevent accidentally slicing them apart.
• Maybe I missed it. How did Phoenix get free of the handcuff linked to her mother's detached hand?
  • It's conceivable that Norman trained her to lockpick among other survival skills.
  • Careful inspection shows she slipped the end that was cuffed to her mother off the severed arm. As to getting it off herself, the above still applies.
• How did the Blind Man get the Phoenix in the first place? Did he just stumble in a fire and beat 9-1-1 to it? And the parents didn't report the missing child (or anyone notice)?