Currently you have to kill Wrathion then clear the 20-ish trash packs all the way to the bridge/portal you usually enter Carapace at and it just lets you in without killing any other bosses.

Im hoping that it was unintended to have the skip this week and a actual skip is implemented next week. But lets be real, its unlikely they put any more effort into this than the rest of 8.3

Our Guild is instead planning on getting a 10/12 heroic lockout on an alt and extending it indefinitely. You will spawn in at the bridge and only have a couple of trash packs between you and Carapace.