passenger comment on AAY facebook page Aug 25, 2015, I believe it was about flight #453 Austin-Las Vegas:

Marilen Acosta-Jallorina‎

"We had an Allegiant flight incident yesterday from Austin,Texas where the airplane had to go back to the gate because something metal broke (loud cracking noise) just before the plane was about to take off. Pilot slammed the brakes and everyone was thrown forward. Thank God for the seat-belts that everybody was wearing. One woman was evacuated for anxiety attack. I do not blame her. We were offered to wait 6 hrs for the rescue plane to continue our flight to Las Vegas, but my husband and I decided Allegiant planes are old planes so no more flying with this airline."