Destroy 3 Sra'thik War Wagons.
The mantid now surround the Temple with their infernal war wagons. The sooner we are rid of those things, the better. You could destroy them with your own weapons and spells, but this will work much faster.
<Ogo hands you a few small casks of hastily-packed explosives.>
Beware of retaliation from mantid that remain be inside the war wagon when it explodes. In fact, I'd stay as far away from those things as possible.