The Vault Won't Open for Cowards

You all wake up shoulder to shoulder in a windowless vault, the door welded shut behind you and a red timer bleeding down from twenty minutes on the far wall. Four brass dials, a riddle scratched into the floor, and a single wrong turn that dumps sand into the lock — every mistake steals sixty seconds you do not have. Someone already touched a dial before the rest of you woke, and the count is faster than it should be. The riddle needs every one of you: one reads, one calculates, one keeps time, one holds their nerve. Argue and you rot in here. So — who trusts whom, and which dial do you turn first, right now?