A faint sound like a gas leak.

You try to quiet down the wimps and wusses in the bus. All the others stay quiet, and like soldier, observe their surroundings.

You whisper abruptly, "Shut up you cowards!"

They listen but faint whimpers can still be heard through their -shut mouths.

"I ain't saying nuthin," a soldier from the back responds.

"Wait, you smell sumthin'?" a Hispanic soldier says.

You use your senses to find the source of the smell. The smell is strong and it originates from somewhere in the building. Pitch black, your surroundings blind you. But tasting and smelling the airborne substance, you find that it is lethal.