This is a scene from 2.08 "The Passage." Will has come to Vaughn with information on the infamous test questions. Working side by side on the Project Christmas investigation- spying never looked so good.
Earlier in the season Will gives Vaughn a mini-lecture on the ways of Sydney's heart. That is one of my favorite moments- when Will seemingly "lets Sydney go" because he knows Vaughn makes her happy. It was a great scene to showcase Will's love for Sydney, his friendship with her and his respect for Vaughn.
Thanks to Liz for the pic and the many others she sent in!