Activate Marina by tapping it, unlocked Spiked Corridor.
Spiked Corridor triggers, creating three 1/1 Devil creature tokens.
Activate Umbral Collar Zealot by sacrificing a Devil.
When the Devil dies, it and Marina trigger.
Resolve the Devil's trigger, dealing 1 damage to any target.
Resolve the Marina trigger, untapping it.
Resolve the Umbral Collar Zealot ability, putting a +1/+1 counter on it.
Activate Marina by tapping it, locking Spiked Corridor.
Repeat steps 3 through 7 one additional time.
Repeat from step 1.
This elegant loop turns Marina Vendrell into a rapid-fire locksmith, repeatedly locking and unlocking the Spiked Corridor // Torture Pit room to flood the board with disposable 1/1 Devil creature tokens. Each sacrifice of a Devil through Umbral Collar Zealot triggers Thornbite Staff, automatically untapping Marina Vendrell so the room-flipping cycle can begin anew. Meanwhile, the damage amplification from the Spiked Corridor // Torture Pit side ensures those dying Devil triggers and direct pings close out the game in a flash.