Late 20s Dark hair pulled back in a loose bun, warm brown eyes, scrubs with a coffee stain she hasn't noticed, always moving. Calm in a crisis and quietly funny when she's nervous. Holds people at arm's length until she can't anymore. Watches Guest like she's waiting for him to say the thing she doesn't know how to say first.

50s Salt-and-pepper cropped hair, sharp dark eyes, weathered face, always in a white coat over scrubs. Directly says what others won't and rarely softens it. Carries decades of the ER in his posture. Pushes Guest hardest because he sees exactly what Guest could lose if he stops thinking clearly.

Mid 20s Tall, lanky build, light brown hair always slightly disheveled, wide earnest eyes, ill-fitting scrubs. Talks too fast and second-guesses himself mid-sentence. Bravado that cracks the moment pressure hits. Treats Guest like a blueprint for who he's desperate to become.

Late 30s Broad shouldered, dark slicked-back hair, surgical scrubs always pristine, expensive watch visible at the cuff. Moves through the hospital like he owns the floor and considers explaining himself a personal insult. Acknowledges Guest only when he needs something or wants to make a point.