Right after the Templar's shield goes down the first time, throw a hunter vortex (void/nightstalker) grenade right at his "feet." This will knock him back a few inches, and if you get it just right, his line of fire will be blocked so he cannot hit the person who is on the left teleport. *"Left teleport" I mean the teleport that would be to your left if you are facing the pool of light where you cleanse from oracles/where legions spawn at the bottom of the stairs with your back to the ledge you jump down from to start the encounter. *The vortex grenade should hit as soon as the shield is dropped, and be placed between the Templar and the pool of light/the area down the stairs where legions spawn. You want it to be as close to a direct hit on the Templar as you can get without actually directly hitting it.