In SAW 2 why did they seem so exhausted, and poisoned?

I just started watching it the're always coughing and stuff...whats wrong? also what is wrong with that Laura(Beverley Mitchell)?

Jeez peoples I really dont like this type of movies but I in a way I do I just want some info because I dont like being unsure....

thank you to all of you who answered my question with out crude remarks...\

I also ment why does beverly mitchel die so suddenly what happened to her she seemed really bad. Like I said I started watching it late in the movie =]

they seem sick cuz jigsaw put
some kind of gas
in the vents and they inhaled it
they're tryna get the cure
which is in the needles

There's a gas going through the vents and infecting them. The gas makes them cough up blood and eventually infect their whole body.

I thought the bad guy was piping in deadly chemicals in the air.

because there is poison in the air and if they don't get out in a certain amount of time they will die

They are stuck in a house that has a poisonous gas in the air.

And Beverly Mitchell is a Kleptomaniac (she has urges to steal things.)

Damn it watch the freaking movie.

and pay attention for god sakes you might get it.

that is because they are getting poisoned pay more attention next time.

They looked like that because they were infected with a nerve agent at the beggining when they were all together in that big room and the recording went off. remember now?

there was a poisin in the ventalization system that was circualting around the house they were trapped in.....

Well now.
It wouldn't be a very interesting story if you knew everything.

The thing with Saw movies is you just have to sit there, and put stuff together as it comes.

If you don't, or try to find out before it happens, it ruins it.