|Your playing rhythm on the Other one and the lead player is
playing B Aeolian.
Your thinking why not play E minor?
Well E Aeolian E F# G A B C D
B Aeolian B C# D E F# G A
are quite similar with the exception of one note and
E Dorian E F# G A B C# D is the exact same notes transposed.
But why play B Aeolian?
The player is trying to excentuate the 5th 7th and 9th of
E minor (B D F#)
Now the 5th in many cases is a throw away note but the
7th and 9th are tantalizing to the ear as is the 4th.
Go ahead dust off those rusty strings just one more time
and fool around with the 4th, 7th, and 9th of scales.
It's quite pleasing to the listeners ear.
You don't need to get bogged down with root 3rd(or flat 3rd)
and 5th in a major or minor progression. Open your ears
to these new possibilites and discover a few of your own.
Maybe you'll fall into accentuating outside notes even
such as the flat 5th. Maybe not.