Posting without waiting for a reply from Robz.
Voltgloss, this should clue you in to if we're on the same page or not, and for those looking for more, it's the best I can offer at this time. If Volt or Robz wish to expand, it's on them. I'll be working:
The 'slip' in question is one that demonstrates a certain knowledge on Mail-Mi's part. A knowledge that I don't honestly believe that he would, in the moment, just happen to know.
Further, he makes an assumption based on 1 piece of information that is, in my mind, an unreasonable assumption unless you happen to have prior knowledge of the situation. That is, piece of Information A should not be enough alone to figure out piece of information B, and yet it's a leap that he made without hesitancy.
That's as much as I can say in explaining the 'slip'. I can't tell you exactly what it was, because if he's in fact exactly what I believe then I would be providing his scummates with the very information I'm trying to prevent them from having. It may well be too late regardless, but this was the best way we (Robz and I) could think to present this given what we (believe) saw.