Three doors held open in sequence, two of them true portals that die the instant the club locks down.
Carl's breach depends on a chain of three doors all being held open at once: the door from Shanty Town into the Temple of The Dagda, the door from the temple into the Club Vanquisher entrance vestibule, and the door from the vestibule into the club itself. Only the second two are actual portals.
Both portals must be kept open at all costs. The moment the club goes into lockdown — expected at any moment — the portals cease to work, but only once they have closed. Zhang reports the vestibule door secured open; Carl holds the club door himself, and once Li Jun finishes anchoring the wires his job becomes guarding that door and keeping it open. The scheme also keeps the Clock Tower Capacitor Wire running unbroken from tower to club interior.
The structural gimmick that keeps the team's route into and out of the club alive.