As I was finishing Root of Nightmare on Master difficulty, I started noticing the Nezarec encounter music has elements of "Night on Bald Mountain." Normally, I have my sound turned down to listen to my fireteam, but when focusing on ads I just hear the horns and string sound an eerily similar to Modest Mussorgsky piece. And also on Master it helps to focus on something, I was humming "Night on Bald Mountain" as I was fighting harder to clear champs for the runner. https://www.youtube.com/watch?v=L2fnn07tyvM for comparison focus on strings and horns.