It's perfect!
Stephen wasn't the sort of person who cowered under pressure. Not even when a patient was dying on the table and he was doing what he could to stop it. He could have stopped the arrow, sent it flying through a suddenly open portal to harmlessly land in some far-flung sea with nary a thought.
But it was safe to say he let out a little exhale of relief when Wanda appeared, because she was the perfect person and friendly face that the archer needed. That, and Dr. Strange's bedside manner? Frankly, it sucked. And he'd be the first to admit it.
What caused him to look surprised was her revelation that he lost his family. Which explained everything. This was Wanda's territory, and he was going to make sure nothing happened to her while she was concentrating on Barton's shattered memories.
There was another thing which needed explaining, even if Strange found no joy in it, "Loki is no longer a threat or an enemy."