"The current is so strong that it could rip open our masks or drag us into a whirlpool," said Totok Subagio, in charge of a group that this week found the plane's two black box flight recorders, after a lengthy, difficult search.
Trained to swim to depths of 45 metres (150 feet), the Indonesian navy's finest frogmen were drafted in to scour the seabed for wreckage of the Airbus 320-200 that went down in a storm last month en route to Singapore.
Grainy images from specialist Singaporean search equipment Wednesday showed the plane body resting on the seabed, with part of the Malaysia-based airline's slogan "Now Everyone Can Fly" painted on the red-and-white exterior clearly visible.
Divers now face the grim task of examining the main body of the aircraft in the hope of finding more of the 162 victims who were on board the plane, believed trapped inside the fuselage. Almost three weeks into the search, just 50 bodies have so far been retrieved.
The currents are so strong they can be dragged sideways and at times appear to be "flying like Superman", he said.
The search has been tough even for veteran divers, with some suffering nosebleeds after spending too long at depths of 30 metres.
Conditions on the surface have also been rough, with some vomiting on their way out to hunt for the wreckage as their tiny boats were hit by waves four metres high.
Most days divers have had only a four-hour window in the early morning when they can search, before clouds obscure the sun and reduce visibility underwater, rendering search efforts impossible.