Lizzy will summon a lieutenant that's vulnerable to the havoc glove subterranean attack. Try to attack when it's in the middle of the platform so you can have the laser track towards you. Squish it's offspring for health if you need it.
Do this a couple of times and the lieutenant will be destroyed.
Now destroy the laser emitters on either side of Lizzy's throne, one at a time. You'll get attacked by little red exploding ants, make sure you replenish your health if you need to.
You can probably destroy all the emitters in two attempts, possibly one if you're really quick.