I thought about this more. Let me know what I am thinking makes any sense.

Is Rick perhaps playing the arpeggioS of the different chord shapes (major and minor arpeggios?) I could be off here but I am thinking that if tried to play the respective scale for each chord, there will be 2 or 4 notes per chord that are off depending on Major or Minor. Penta=5 note or Major=7 note arpeggio...since chords/triads only contain 3 notes.

Technically, I could play in Bm penta and focus on the right notes. It will work but I would likely sound a little off. Likely, in the original tune, they do both- the arpeggios up and reverse, and play licks that fall within Bm scale. Despite being in Bm, most of the chords are MAJOR.