The scherzo is in 12/8, an unusual time signature, is marked allegro scherzando, and is in C minor. Its quiet and spooky. You expect someone to sneak up behind you and bite you on the neck. At 1:58 youll notice that the pianist has to play a middle C using 5-3-2-1 on his right hand sequentially as the time signature goes briefly to 18/8. Its little things like this that make Rachmaninov so intimidating for us mere mortals who are pianists.
At 2:17, for his trio section, Sergei switches to 4/4 and A-flat Major for the kind of melody a lesser composer would have used in a slow movement. But Rachmaninov, the master of melody, has no problem using it here. The cello soars over the piano for a perfect tune. Your screen may go blurry when he resolves it.
He brings it back to the scherzo material, and the coda ends it quietly in a very spooky manner.
Rachmaninov: Cello Sonata in G minor, Op. 19, second movement