In this scene from the next episode of DC's Legends of Tomorrow, we see Sara Lance and Martin Stein have gone undercover at a local hospital. Sara helps a fellow nurse with an overly aggressive doctor and may have found a new friend. We also see that Vandal Savage is working in the hospital as Dr. Curtis Knox.
The name Curtis Knox is an Easter Egg of sorts from Smallville. During the seventh season former Lois And Clark actor Dean Cain played Curtis Knox, an immortal doctor who experimented on the Kryptonite affected. According to Bryan Q. Miller, Knox was originally intended to be Savage in the episode of Smallville but the character became off-limits so the name was changed.
DC's Legends of Tomorrow airs Thursdays at 8 PM on the CW.