JustABill is correct. FAIL.
The whole point of the teaser was to make you think she gets killed. And, by hitting 2 birds with 1 stone, make it appear that the killer this time is far more aggresive and has - as Gale taunts - the guts to kill her.
keep in mind; Gale Weathers, along with Sidney and Dewey, have a long history with this sort of thing. People in Woodsboro - if not America - know who they are and what they've been through. Killing Sidney or Gale or Dewey is like killing a novelty celeb. That's why the chase is so much more menacing this time around, I feel. The killer even says on the phone, "You're a survivor, aren't ya Sidney?". He knows her death would be a huge deal because of her/their past and story.
My bets? None of the original 3 will die. In fact, I recon we'll see them fight harder than ever to stay alive, since they should be pros at it by now.