Okay, so let's assume both teammates do not have trinkets, or do not want to use them, even though you're faced with a mage who is going to kill you in 8 seconds after your teammate is polymorphed. At the time the mage gets LoS'd from your awesome .2sec pushback, he turns to you, polys you, and focuses on your healer, killing him in 8 seconds instead? At this point, assuming the healer is still alive, you get out of poly and you're already out of LoS, unless your teammate has ran back out towards you. If he was capable of killing you in 8 seconds there's no reason why he can't kill your healer. But we'll assume he can't kill your healer; He pet novas your healer out of LoS leaving you to pop sprint (you know, if you want to) so you can get in there in time to gouge and buy your healer some time to heal, and then whoop his ass. But wait; at this point you've both just presented yourself in LoS. By this point blink is off CD and a frost nova follows, leaving him to finally poly your healer regardless and then blow you up in 8 seconds.
But come on dude, look at the problems here.
vs a mage, especially a frost mage, you're telling me you're going to reserve CDs instead of just using them to blow his non-healing ass up, or force him to blow an AGM?
this mage is going to come at you 1v2 willingly?
this mage is going to kill one of you in less than 8 seconds?
the mage is dead regardless of your ranged weapon, the slight pushback will have only been a nusiance in the entire battle.
no mage in this game is fast enough. it's fun to think about theoretically, but this situation is VERY unlikely to EVER occur, especially in a pug. there are too many teammates around, there are groups of people larger than 1v2 fighting, and if you got killed by some guy who was able to pull these kind of moves while you were away from your entire team you deserved to die anyway.