According to this comment (https://www.reddit.com/r/gaming/comments/4dybvk/i_think_i_discovered_a_new_easter_egg_in_mike/d1vy7y6 https://www.reddit.com/r/gaming

According to this comment (https://www.reddit.com/r/gaming/comments/4dybvk/i_think_i_discovered_a_new_easter_egg_in_mike/d1vy7y6 https://www.reddit.com/r/gaming/comments/4dybvk/i_think_i_di...) the bearded man doesn't do anything during other fights, so this is not a random animation.