Madonna falling in Rio back in December got me to thinking, naturally enough, about Mulholland Dr.'s use of "Llorando," Rebekah Del Rio's Spanish cover of "Crying." There's a lot of gravitas to gravity -- with one slip, the reality of artifice can be exposed. At the club Silencio, when the character of Del Rio (played by Del Rio) falls, but her singing continues, David Lynch is playing around with Bertolt Brecht's epic theater and his notion of estrangement. By having the work remind the audience of the layer of representation intervening between them and the emotions they're experiencing, Brecht hoped to create a more politico-rationally engaged experience -- that is, one of empathy, not sympathy (the former being of intellectual understanding, not the latter's identification).
However, Lynch turns estrangement on its ear by using lip-synching as the emotional crux of his film. If you'll remember, the scene occurs at the point where the fugue world of Betty is fracturing, and the reality of Diane is seeping in. Diane had killed her lover, Camilla, out of jealousy, replacing her in the dream with the amnesiac Rita. Of course Rita can't remember who she is, because she's a manifestation of Diane's oneiric state, a displacement of Camilla, with all the bad stuff repressed. As Rita, she's a ghost, pure desideratum, or Diane's objective (objectified) correlative of the real deal. (In fact, the same applies to Betty; she's Diane's idealized self.) Just as the illusion of the film's representational quality is most exposed (Lynch's "eye of the duck" scene), Betty and Rita begin sobbing -- and (provided the Silencio sequence works properly) the audience along with them.
