Just Stay A Little Longer....

"dancing somewhere to the left of the middle of the room."

Dunno why, but having purely explanatory sentences that are very plain and devoid of emotion within emotional pieces is very effective.

The transition from the fantasy/dance scene into the crash works well.  No warning, but somehow integrated into the mood of it.

A couple of things:

If you're planning on directing or guiding readers (this only applies if you're writing for an audience rather than just for yourself or catharsis), using paragraph breaks often gives you some degree of control over how a piece is read; breaking the piece into paragraphs, but still keeping the transition from the dance to the crash within the same paragraph makes the whole thing more smooth (and, paradoxiacally, more affecting).

The figure of Donnie was somewhat confusing.  At first I thought that you were referring to the narrator's lover, since you hadn't named her at that point.