She stole Mendoza’s plan to free the hostages, hoping to receive time off her sentence for the good deed.
To start, Red and the rest of the inmates in the bunker will likely feel a great deal of guilt.
But if she let Gloria got through with the plan, the matriarchal character would be safely outside of Litchfield’s walls during the moment in the bunker.
Mendoza wasn’t actually involved in the confrontation with Piscatella or the shenanigans in the pool, so if she dies it’s partly Red’s fault.