The Pitt: Whats a code black?

Brace yourselves, Pitt Fiends! (Is that what we're calling ourselves?) Because episode 3 of Season 2 just dropped a major cliffhanger. As if Dr. Robby's lie doesn't have us stressed enough, now we've got a code black to deal with!?

Spoilers and speculation below for Season 2 of The Pitt.

For those unfamiliar with hospital terminology, a "code black" in this case means the nearby hospital will be diverting all its emergency room patients to Dr. Robby's trauma center until further notice.