How to escape ''Poseidon''

Wolfgang Petersen is best known as a director of CG-heavy hits like Troy, so fans may fear he’s gone soft as he trumpets the art film within his latest disaster flick. ”People will be surprised by the emotion,” says Petersen. ”It has this wonderful idea for turning your life upside down.” No worries, folks. Poseidon is still about a desperate race to the corpse-riddled boat’s bottom (which is now, of course, the top). Josh Lucas, Kurt Russell, Richard Dreyfuss, and Emmy Rossum headline an ensemble of disposable stars — perhaps too disposable, given the film’s somewhat waterlogged debut at the box office — but the film’s biggest attraction is the boat itself. Here’s the route the lucky few Poseidon passengers followed to escape the doomed leviathan, and how the cast and crew themselves survived to tell the tale.

1. BALLROOM
The crew built two sets — one lavishly decorated for New Year’s Eve, the other an upside-down scene of chaos. Despite all the labor that went into the project, they took the greatest pleasure in destroying their work. ”That set had giant [water] tanks that went almost to the ceiling,” says producer Duncan Henderson. ”When the water broke, it shook the stage.”

2. ELEVATOR SHAFT
Not everyone makes it across, but Rossum wanted assurance that she’d live. ”They had me hanging in a harness and there were no crash mats on the floor. I said, ‘Can’t we put down some mats just in case?’ They said, ‘We don’t want to give you a false sense of security.”’

3. GRAND STAIRCASE
Like the ballroom, the lobby’s five-story staircase was built right-side-up and upside down. A team of 100 workers spent five months creating the flooded inverted lobby that Lucas bravely dives into, swimming under a wall of fire. ”You can’t go up [for air], and it really becomes something dangerous,” says Lucas. ”I would literally go home and spend time in my pool holding my breath as long as I could.”

4. AIR DUCT
Intense claustrophobia strikes one of the characters (though not Rossum), but the very game cast handled their ”week and a half inside a box” rather well. ”Josh and Kurt are sort of macho guys,” says Henderson. ”No one else wanted to be less than that.”

5. BALLAST TANKS
To escape the seeming dead end of an air-filled ballast tank, Lucas’ Dylan floods the chamber, hoping the pressure will cause a hatch to open. Rather than dangerously swamp the tank, the crew worked backward, carefully lowering the pliable roof of the set onto the floating actors. ”It was very nerve-racking,” says Henderson. ”You want to make sure you don’t lose track of anybody.”

6. BROADWAY
Built on a teeter-totter that could generate waves, the long corridor allowed Petersen to stalk the survivors one more time. ”The bad guy is the water,” says Petersen. ”It’s really interesting to make water a terrifying element that comes around corners.”

7. BOW THRUSTER ROOM
A giant propeller stands between the passengers (led by Russell) and safety — one they need to blow up to escape. ”They set up a propane blast to make the fire explode bigger,” says actress Jacinda Barrett. ”I stepped away [and] the blast went much higher than expected…exactly where I would have been standing.”