There's a cheese to get around it? I've always done it legit. It's not difficult at all. To the people complaining about rockets. It takes 1 gjallarhorn from a level 31 to take out each shrieker. Just assign who you send in on each side. Maybe hit the final wizard 2-3x with gjallarhorn and use bullets and sticky grenades for the rest. There's tons of time. With six fireteam members, there's no "wasting" rockets on her when it literally takes 2 rockets for 3 fireteam members.