While deep down Saren has goodness within him, his judgement and morality have been clouded by all the wrong doing that has come upon him and his sister. He has an insaitable hatred towards humans, one that often leads to snapping jaws and injury, and won't even go near the handlers that manage the pack Shepard resides in. Knowing that she has grown attached to them, he does his best to stay away from the pack so he inflics no harm on the handlers, but despite that he's always within earshot of his sister.