I suspect that at the time of that Chronis hearing, JM was using Flores & his notes/reports (and the autopsy report). Flores talked to Horn (JM didn't) and thought it was gunshot first so he misinterpreted something Horn may have said and testified to that at the hearing - just as he said during the trial, IMO. As busy as both prosecutors and ME's are, and with the heavy caseloads both have, I doubt JM & Horn talked directly for a long time. Prosecutors don't investigate cases, the PD does and prosecutors work off of their notes/records, giving the detective a call if there is a question, etc. (They do have investigators in the DA's office, but they generally don't do this kind of casework either) IRL, many times prosecutors don't meet with a witness- especially a known expert that is used to testifying - until just before their court appearance unless they have a question or notice a problem. When my husband was a detective, he'd often go over the case with the prosecutor in the hallway before the trial - no, not on capital cases (they meet on those) but that's how it worked on some pretty serious charges/crimes. So I don't think they changed their opinion as much as discovered Flores' error once JM and Horn got together, whenever that happened. As for the typo, IIRC, the ME's office was seriously understaffed during the time of that autopsy. Missing that "not" was probably pretty easy to miss, and I thought Horn looked seriously puzzled when that came up in trial.
We know where the bullet entered the skull and where it crashed through the cranial plate (leaving a large hole) before entering the facial area - they showed that picture in court. There is no way that trajectory between the skull & the hole in the cranial plate missed or even 'skimmed' the brain. Horn also said that hitting that bone/plate may have changed the original trajectory so it's not necessarily a straight path from the entry point to where the bullet lodged. He testified there was very little bleeding, not even in the sinus area. Cases where people were able to move & survive these shootings generally involve a path straight from front to back, high up in the skull - not one where it crosses from side to side, and perforates the cranial plate like this one did. He would have been unconscious and probably wouldn't have survived it for long. :moo: