He strikes me not with the moodiness, but with rigid thinking. His preoccupation with finances, so amply shown after his wife disappeared, what is it? Obsessed about money...
I agree, although the past few days I've been thinking about what BM was up to, that weekend of May 10.
If we are to believe he was at a work site on Saturday morning, goes home to do hike and bike with wife, then goes shopping, then goes to another worksite
at around midnight to do some minor "mechanical thing" to a piece of machinery, then gets up early (estimated 4 am) to leave the house at 5 am, to drive 3 hours to Broomfield, where he does something or other...
Sounds very high energy, even hypomanic to me. The obsession about money is common to many bipolars, btw, especially when they're dipping in and out of depression (they become convinced they don't have enough money, they see themselves as poor, then they launch themselves into manic/hypomanic efforts to get money).
I dunno, it's just a thought. In the very little we've heard him actually say, his speech is rapid, even forceful at times. He is far too eager to talk to TD, imo, seems to have his mind jumping around, speech is coherent but rapid and many thoughts trail off. Some of the phrases he uses ("Let me tell you what happened!" have already been analyzed here, but it does sound a bit grandiose, given that clearly no one knows what happened to Suzanne (except, perhaps, BM himself - yet what he then does is expect TD to believe his rather incoherent account).
He also does that thing where he exaggerates (400 tours of duty, 200 mile search radius, continues to search by bike day after day, etc.). That's considered "expansive speech" (in write-ups of this kind of behavior, we would never say "lying," at least not in any clinical record).
Naturally, all of this could be merely the result of the events he was living through, for sure. But on the weekend of May 10, he apparently went almost entirely without sleep (until he crashed at the hotel?)
If he wasn't busy covering up a crime, it is unusual behavior indeed (to be fiddling around with a Bobcat until after midnight on Saturday, when it wasn't needed for the job in Broomfield, when he had already had a full day and was aiming to get up very very early on Sunday).
I probably entertain this point of view in part due to my own hope that BM will actually crack and at least say something that's even more incriminating (he appears to have some control over his own behavior - although I am mystified by why he moved out of the family home and is living in a condo in Poncha Springs - that was impulsive, and it's possible the move to CO was impulsive as well).