Far down in the engine-room, below five flights of bent ladders, the floor slopes sideways and is covered with oily muck.
It is pitch black except for the odd generator-powered light, just a faint glow amid the gloom.
The smell - a putrid mix of salty air, heavy fuel fumes and thawed, rotting food spilled from busted containers - is almost overpowering.
And the noise is terrifying.
The sounds of howling wind and crashing waves combine with a cacophony of creaks, bangs and groans of steel grinding on steel.
These of the death throes of the MV Rena, one of the most perilous wrecks that a world-renowned team of salvage experts have seen in their careers.
The severed hull grinds against itself as waves wash back and forth through slowly widening gashes in steel 18mm thick.
Pancaked rows of containers - many 12m long - tower high above, always threatening to crash down.
The salvors must keep their balance on a sideways, ever-swaying deck soaked in slippery oil and water.
Every few moments, another swell slams the hull, rocking it again.
Weighing heavily upon the salvors' shoulders is the hope they will be able to pump away all of the oil still in the Rena's tanks before the ship breaks up.
But first they must empty one port-side tank - and then try to get to the 356 tonnes in the tank on the other side.
With a five-day window of fine weather and a booster pump that managed to clear 171 tonnes by yesterday afternoon, there is optimism, but the job is dangerous.
"Everywhere, there's risk at the moment," said Svitzer Salvage master captain Drew Shannon, speaking exclusively to the Weekend Herald.
"It's not like working on a normal ship - the ship is listing, it's creaking and groaning. The whole ship is an area of concern, clearly."
The most dangerous area was the ship's starboard side, where the deck was covered with water and leaning into the ocean, and piles of containers were listing sideways.
"That's a place we are not working. Especially when it's high tide, there's waves coming over the side and you can definitely see there's water on deck."
Mr Shannon said salvors were working in areas where danger levels had been well assessed.
"We do become attuned to it and it does take time. They've all had the training on how to deal with these situations, but there are concerns - and we have vessels on standby."
In the engine room, where things are much more stable than a week ago, salvors worked in pairs for safety reasons.
There, water had been pouring in from a starboard-side manhole.
Divers were sent down to check it as salvors prepared a coffer dam - an enclosure to keep water out - to access the starboard tanks.
"No two jobs are the same and each has its challenges," Mr Shannon said. "So we have to adapt to the conditions and the needs of the casualty ... and we just have to go forward with this challenge as with any other."
Maritime New Zealand's salvage unit manager, Bruce Anderson, has been on board the Rena and knows what the salvors are up against.
"These guys love challenge and enjoy trying to understand the issues, but even they're saying it's the toughest job they've ever had to do - it's complexity upon complexity upon complexity."
He tried to put their precarious workplace into perspective for Weekend Herald readers.
"Just imagine your office on a 21-degree tilt and having to walk up and down the stairs, and having to manhandle equipment on board the ship ... There's oil and rotting food coming out of containers and it's slippery ... It's a dangerous place to work.
"The salvors are telling me the creaking and grinding of the vessel is continuous as it's always being knocked about by the waves - I wouldn't say it's eerie, but it's quite spooky.
"It would be really interesting for people to hear the grinding sound being made as the two parts of the ship work together. It's hard to describe ... It's like metal grinding."
Svitzer spokesman Matt Watson said: "When you are up close to it, it sounds like Jurassic Park - you hear this groan, and then a crack, and then a roar like she's kind of writhing in the water.
"It runs from one end to the other and then it just seems to ricochet back. It's a very interesting sound, to say the least."
Mr Watson saw the stricken container ship as a lame, dying beast.
"It's like the ship is trying to talk, saying, 'Help me, get me out of here'.
"She is a very sick and distressed creature, and it's almost as if she knows she's got these salvors crawling all over her and she's crying."
The salvage team have been flown in from around the globe and are helicoptered to the wreck every day.
Tonnes to go
* Fine weather is expected over the weekend - aiding efforts to offload oil from the Rena.
* 171 tonnes of oil cleared from the ship - 15 per cent of total load.
* Another 3km of beach has been reopened.
* No new reports of oil slicks.