The microwave corridor was a hallway lined with directed-energy weapons within the warship Outer Haven. The weapons emitted certain types of microwaves at a frequency that would cause severe pain to anyone passing through them by heating the water molecules in their body. Its purpose was to deter unauthorized personnel from accessing the GW AI server room at the end of the corridor.
Liquid Ocelot utilized the microwave corridor during Haven's battle against the USS Missouri, in order to prevent a boarding party from accessing GW. Naomi Hunter had earlier leaked data regarding Haven's defenses to Mei Ling's crew on the Missouri, sparking fear into all the crewmen, except for Solid Snake, who volunteered to traverse the corridor and infect GW with a computer worm.
As Snake made his way further into Haven, Raiden caught up with him and offered to head to the server room in Snake's place, claiming that his cyborg body could withstand the microwave emitters ahead. However, Snake refused and left Raiden to hold off Liquid's Haven Troopers, who were closing in. When Snake approached the door to the corridor, Otacon used the Metal Gear Mk. III to gain access and the heat from within immediately hit Snake. Heading onwards, Snake was slowed down by the immense pain he was forced to endure, his OctoCamo suit providing some limited protection before deteriorating from heat. Snake was eventually forced into a crawl, but encouraged along by Otacon via the Mk. III (itself beginning to suffer damage), he dragged himself to the door of GW's server room through sheer force of will, and away from the path of the microwave emitters.
While the microwave corridor failed to prevent Snake accessing GW, the injury they dealt significantly weakened him, causing him to be overwhelmed by Dwarf Gekko in the server room, which were only disabled by the timely intervention of Otacon.
Behind the scenes
The microwave corridor gameplay was pitted against the ladder climb from Metal Gear Solid 3: Snake Eater on Versus Battle.
Epic, Gripping, Heart-Rending Cinematic Crawl
Hazardous to Old Snake’s Health
Tragic trials & scenes like the microwave hall are a memorable example of what separates a METAL GEAR title from just another video game
METAL GEAR SOLID: THE LEGACY COLLECTION"
- ―The Microwave Hall description in Versus Battle