I was chorusing a fighting game BGM if I had a mitt in the park

At the city park in Manhattan in New York City Park is a movie where two men are practicing fighting sports at the city park and people around them start choraling the BGM of fighting game "Mortal Combat" abruptly .

Details are as follows.
I can not practice properly if I suddenly do such a thing.
YouTube - Mortal Kombat in Central Park


The people who suddenly started singing are the A cappella group DeCadence ("dee - 'kay - dence") of the University of California. It seems that the two people practicing in the park are really red people.

The official site of DeCadence is below.

DeCadence Boldly Going Where No One Else Wants To