"By keeping that pressure in there, it supports the fluid out of the lungs," said the Department of Homeland Security instructor, as he showed South Mississippi emergency responders how to treat a victim.
The first responders are "treating" a medical mannequin.
"How can you start gathering some more information?" questioned the teacher, as the paramedics and firefighters assessed the situation.
The scenario involves casualties on a commuter train.
"Did they see anything unusual on the train?" asked a Biloxi fireman taking part in the training drill.
"How many of these kits is he going to get?" said one student, as the "dummy" was administered doses of medication.
"Two to three, because he's conscious and twisting," came the quick reply.
"A pressure of 113. There you go," said a paramedic monitoring.
The rubber patient is more than your basic CPR dummy. It's a high tech tool that actually responds to treatment.
Mike Schuler is one of the instructors for the federal Department of Homeland Security.
"We can make him tear, we can make him drool. He even wets himself. And those are all typical things you would see with someone exposed to a large dose of a nerve agent," said Schuler.
"We train on haz-mat all the time. We train for the chlorine and the ammonias, but this one involves weapons of mass destruction where you get into the nerve agents and you get into some of the things that we don't see on a normal basis," said Biloxi firefighter Kerry Borden.
A million dollar regional response truck is also not seen on a normal basis. Federal money paid for the truck and all the specialized gear it carries. It is designed for disaster.
"And it could be anything from a large haz-mat spill, a natural disaster, to a weapons of mass destruction event," said Gulfport Fire Chief Pat Sullivan.
The training will leave South Mississippi better prepared for whatever may threaten.