You tried and still failed. You are not admitting that the likelihood of this possibility could possibly be much higher or that you can possibly be wrong. Cover all angles mon.
There's no direct cause and effect link between Sylvanas sounding retreat and Varian dying. If anything the fact that Horde's support vanishing caused the Alliance to retreat earlier led to Alliance leadership not getting smashed to bits by the Fel Reaver meteor while they were still on the ground.