Tarak had heard Surani shout. He immidiately looked upward and witnessed a dragon breathing fire for the first time in his life. His surprise changed to a look of seriousness very quickly, realizing the immidiate danger of the situation. He searched for something to hide behind should the creature try and focus on him. At best, there were the destroyed remains of High Hrothgar, but that was out of the question. Tarak would simply have to stay extremely far backward. 
He primed his own spell of Conjure Familiar, conjuring a wolf; it wouldn't do much unless the dragon landed, but even then, it's impact wouldn't be very useful. He needed to learn more offensive spells if he wanted to contribute to such battles.