It must have been overwhelming to have spend the past 7 months wishing you have gotten there sooner, and tirelessly pursuing justice for someone you thought had died in front of you.

Then now, the same person stands in front of you, alive and well, and says "I'm so sorry."  

His reaction - I love it best. So emotionally appropriate, considering what Morgan had to go through in Lauren, and what he did for Emily in the months preceding this episode.