If I had a doctors appointment booked in advance and didn't tell my employer and agreed to attend a meeting at the same time, I would expect some come-back form it. As I say, if it was a last-minute emergency, then fine. But if it was just "I feel a bit unwell, I think I will see the doctor", I'd let my employer know what was happening in time enough so that they could organise a replacement for me. If I thought "I can go to the doctors and still make the meeting", then unless it was something bad, I'd expect to be in a bit of trouble about it if I couldn't make it back in time.
Well, imagine then that you have spent almost 2 hours doing something pretty dangerous under extreme physical and mental stress. You feel something is off to the extent that decide to visit the medical facility. How much of a concern do you think that the national anthems are to you at that moment? Also, a "meeting" that you are supposed to attend probably depends to a certain degree on your presence, the playing of someone elses national anthem does not.