If you tank him with your back against the wall (I'm assuming you are doing this) , you have to run through him to get out of range. You might do better if you tank him in the open so you can run directly backwards, giving you more time to get away.

If your know that your party has high DPS you can have your back against the wall. Rotate Sentinel, Aegis Boon ,Divine Veil +Stoneskin (If you are on full HP) and Hollowed Ground if necessary.