I believe we're aware of this.
Ideally differences among particular interviewers in an MMI are irrelevant (although CASPer states their graders are "extensively trained and vetted" on their website to account for subjectivity, and MMIs are often CASPer 2.0), but that was certainly not the case during my particular interview. A few of my interviewers followed along with the same structure of previous MMIs I've done, others jumped directly into their follow-up questions without letting me respond to the original prompt. It was clear that the expectations for the interviewers were not as consistent or clear as they could have been, and that variation could very well have been a result of volunteer discrepancy. Who knows? Regardless, it'd be shortsighted of me to let this experience take away from the program and what it stands for.