Meredith and Winston faced off in the OR on the latest episode of Grey's Anatomy, which was a professional milestone for actor Anthony Hill in itself. "To work with Ellen [Pompeo] on the show that she's the titular character of - and not just be passing in the hallway and saying, 'Hey,' - but actually working on a medical case, and one where we have differing opinions on how to approach something, it was fun to play," Hill, 37, exclusively told Us Weekly ahead of the Thursday, October 23, episode. "It was interesting." In Thursday's episode, Meredith Grey (Pompeo), Nick Marsh (Scott Speedman) and Winston Ndugu (Hill) joined forces for a risky transplant surgery where two parents each donated a portion of their lung tissue to their chronically ill child. Winston, for his part, had been more wary about risks of the living donor transplant to balance out Meredith and Nick's willingness to dive in. "It's dynamic, and it was challenging for me," Hill told Us of his onscreen banter with Pompeo, 55. "That's the kind of [scene] that I enjoy, and to get to share the screen with Ellen is this rite of passage that I haven't gotten to do in a medical setting yet. It's been really enjoyable." 'Grey's' EP Teases How Ellen Pompeo, Scott Speedman Will Be on Season 22 According to Hill, it was equally fun to film opposite Speedman, 50. (Speedman's Nick is Meredith's love interest, both of whom often visit Seattle's Grey Sloan Memorial from their new Boston home base to assist with difficult cases.) "That's fun for me because I love them as actors [and] I love them as characters," Hill said. "And, to get in the mix and sink your teeth into a medical story that has some weight to it, you can't beat that. That's the best part about the show." Hill had joined Grey's Anatomy during season 16 as the love interest to Meredith's half-sister Maggie Pierce (Kelly McCreary). Ellen Pompeo, James Pickens Jr. and Scott Speedman in season 21. Disney/Anne Marie Fox "When I joined, to be honest, I didn't know how much longer the show would go. You never know when you're talking about 17 seasons, like, how much more story can they create," Hill recalled to Us. "But, these writers keep finding a way to do fresh things and inventive things that are innovative to match today and be timely." He continued, "I'm always ready for whatever, [which] you have to be and they pull from headlines [and] from real medical situations. It's very timely and fresh and there's, oftentimes, a shock factor that people think is made up, but it's the real deal. That's kind of what's brilliant about Shonda Rhimes making a medical drama is that so many stories are possible through that." Will Grey's Anatomy's New Timeslot Impact Story Lines? Showrunner Explains Winston has also evolved from Maggie's love interest into a main character in his own right. (Winston and Maggie divorced in season 20 before McCreary's departure from the show.) "[Winston is] not just a doctor and a love interest now, [and] we're starting to see some dimension to a guy, and we're starting to understand why he does some of the things that he does," Hill said. "It's been fun to kind of evolve and grow and try to figure the guy out because it's a constant challenge, but a fun challenge for me." Grey's Anatomy airs on ABC Thursdays at 10 p.m. ET.