It's definitely tight. You need the whole party to know how to press their buttons, otherwise it's an issue. Now that our group knows the fight, we can clear even if we get a damage down (when someone messes up a tower) and with 2 deaths or so. But that's with everyone using food and pots, holding burst, everything. I'd slightly nerf it, personally. This is content people do in PF and PF is notoriously bad when fights are tightly tuned.