The way I do it solo or with 2 people is to run in the left door, shoot 2 rockets at the wizard, 1 at the shrieker then rush out to the middle . Then do the same in the right , go back middle. Then pop a synth and slowly snipe the knights in the left side and kill the acolytes ( nothing except thrall spawn if you do this). Then just wait for the liturgy and you're free to either snipe or rocket ir yut. As soon as she dies just run outside and take your time sniping adds from the Boomer towers