Narcissists can view things like mood and emotion almost like the weather, not as their own personal emotions, but as a vague sort of miasma hanging over the room. So if the narcissist is mad or embarrassed, the whole room is, according to them, and any evidence to the contrary is just a "lie". So if they see behaviour they don't like, they interpret it as if it had just started pouring down on a picnic sort of thing.

Additionally, special events act as a major source of stress and drama for narcissists, if they aren't the centre of attention, they have to play nice so they don't come across as the "bad guy" but if someone else "ruins" the event, then they get to act as mad as they want, because someone else is the designated "bad guy" of the event.

It's very non-intuitive psychology and difficult to understand if you've never been around narcissists.