|The Stand (1994) [Woman in Store]: Shot repeatedly in the chest by Richard Lineback during a convenience store robbery.
Adaptation. (2002) [Laroche's Mom]: Killed in a car crash when a van hits the back of Chris Cooper's car while Chris is backing out of the driveway and Sandra is in the back seat. (Thanks to Hamish)
(Note: As a professional stunt performer, Sandra has probably "died" for several other actresses, though I don't know any specific examples.)