I'm trying Castlevania: Symphony of the Night

[TomGuycott]

Actually if I remember correctly (and correct me if I'm wrong) I think if you go through a boss door you can quickly retreat back once you hear there's no music in the room. However, I think it's impossible to do if the boss immediately initiates a cutscene, or if the boss is right in front of you when you enter, like in a smaller boss room.