Complex sentence: Everyone at the reunion comes out to wave goodbye as they take off, except for Christie, calling out for Billy, has her dress blown up by the chopper, further humiliating her to Romy and Michele's delight.
Split into simpler sentences: Everyone at the reunion comes out to wave goodbye as they take off, except for Christie. As she calls out for Billy, Christie has her dress blown up by the chopper, which further humiliates her much to Romy and Michele's delight.