The Gentlemen of Azov / Ukrainian Marines

When I visited this unit in 2015 escorting a journalist, their guys in the trenches told me that most people there had two degrees, while most people on the other side of Shyrokyne had two years in prison.

https://twitter.com/cossackgundi/status/1498924339651137539

It starts off with him playing Bach’s Prelude and Fugue in C Major, BWV 846. Then pivots to something else at about 23 seconds. If anyone could tell me what the something else is, I would dearly appreciate it.