In the promo for the viral episode, we get a real gross-out moment when a kid flat-out sneezes in Arizona's (Jessica Capshaw) face — the snot going from his nostril to her visage in disgusting close-up.
From there, the sickness spreads like wildfire — even affecting Derek (Patrick Dempsey), who boasts "I don't get sick" before promptly getting sick, doubling over and yelling, "Get away from me!" (That's what we like to call irony, good sir.)
Here's ABC's full synopsis for the infectious installment.
The hospital gets inundated with flu infected patients, which causes the doctors to slowly fall ill one by one. Derek must fight off the sickness as he prepares to give a speech on brain mapping, and the residents place bets on who will fall ill first. Meanwhile, a new doctor at the hospital gives Alex [Justin Chambers] a glimpse into an alternate form of medical practice.
Grey's Anatomy Season 10, Episode 18 — "You Be Illin' — airs Thursday, April 3, at 9 p.m ET on ABC.