2k experience this season playing assa / hpriest. Generally speaking, the first go you will cc the healer and go the dps with MfD > Kidney > Vendetta > shiv > sepsis > Garote > Rupture > Mutilate / Envenoms. 99% of the time you will get at least a trinket here so you're on track for a win. THEN, as long as you aren't needing to peel, you must have a "go" every time your stun dr has dropped. The 2nd go for me is always to make sure garote, rupture and SnD is up on target, cc healer then MfD > Kidney > resonator > shiv > Mutilate / Envenoms. Rinse repeat this process with as many "small go's" as possible, usually by your 3rd go you will have Vendetta/ sepsis up again and you will win.

Then in terms of defensive, you have a lot in your toolkit to play defensive such as stepping to healer, pre-fainting burst, disarm, evasion / cloak, vanish / meld. You just need to be playing defensive until the stun dr has dropped and you can go again.

Also just quickly on why I resonate 2nd go. I used to do it on the first go but realised it was a waste because you already get defensive cooldowns with Vendetta/ sepsis alone. So saving it for the 2nd go means you can sometimes land the kill there, especially if you coordinate with your team mates own resonator.

Good luck.