I'm so sorry you and Miso had to go through that. All my best wishes being sent your way. Try not to beat yourself up, we all make mistakes. I know, easier said than done, I'm great at beating myself up (but working on it). My lil' Hognose escaped a while back and I only found out cause he was face to face with one of my ferrets....ugggh. I got lucky there, no harm was done. But you better believe I have double and triple checked his enclosure every time I closed it since (screen top, I put it on wrong).
Thank you for sharing your story, I'm sure it wasn't easy. But hey, it's worth it if it helps someone else out in the future. Good on you
P.S. I'd have cried too...and I'm a 41 year old guy. No shame in that. I don't care what anyone says.