I don't think that Michael is hiding anything more from the group about Randy than usual.

The only person he told the story of "Randy & My Broken Arm" to is Datu. So Datu and the journals are the only ones who know it. I don't think there's been a lot of free time for journal transcription or review lately, so no one else has this info.

I think the whole story is being told to us is a flashback. So we have all the peices we need - but several characters do not. Will it lead to the loss of more lives? Only time will tell.