The effect is instantaneous. The officers are highly trained for all kinds of dangerous situations. They know better than to question a criminalist when she tells them to take off. So they run at measured paces away from the building, which they assume to be the epicenter of danger. But Catherine's not so sure… the small bombs could be anywhere… could have been set at anytime. Still, it seems most prudent to move away from where the first explosions took place.
Brass is at her side as she rushes away from the device with the rapidly ticking down monitor. He shouts into his walkie-talkie, "Grissom! Do you read?"
"Grissom here," he replies somewhat nonchalantly.
"We got a problem…" Brass begins, unsure of how to break the news that things are about to get even more hazardous for the two CSIs trapped in the filtration plant. "Catherine found some sort of transmitting device… We think there are more bombs somewhere on the site. And they're going to go off…" he looks to her for more information.
She reads his mind effortlessly. "About a minute and a half left," she grits.
"Do you hear anything? Are the bombs in there?"
"Hang on," Grissom says distractedly. He puts his walkie-talkie back on his belt without another word.
Sara's got her flashlight out, examining the stairs. "Do you hear that?" she asks rhetorically. He shines his flashlight down into the depths of the basement below them. He does hear some sort of pulsing frequency, high-pitched but faint.
"It's coming from down there," he says, indicating the cistern below. "I'm going to check it out." He starts climbing down the flimsy staircase until Sara grabs his shoulder. The light illuminates her face and he sees her expression is one of… sadness? Resignation?
"You know what that sound is." Her voice cracks slightly and her hand tenses on his shoulder. "It's the same sound as before, but it sounds different because it's gotten water in it. It's a bomb, Grissom."
She's right, of course. The first bombs were in the tanks, designed to flood the room, force them into the stairwell. The next one is below them and will probably cause the building to collapse. How much damage it will do depends on the amount of explosives used—and, of course, there's no way to know that. There's not enough time to find out either as they have less than a minute left, by his calculations.
He pushes past her and opens the door of the filtration chamber. If the cistern goes up, they want to be as far from it as possible. "In here," he commands, putting his natural aptitude for authority to good use.
She obeys automatically and he follows her through, bolting the door behind them. The room is utterly devastated, a mass of twisted metal, burned plaster, and thick, black liquids that pool everywhere. Still, it's safer than being directly above the cistern. The door they came in is completely obscured by huge fragments of steel and its surrounding walls have collapsed against it. Apparently, this side of the room took the most damage, a point that Grissom wryly notes was most likely intentional. Clearance by the bomb squad or no, they will not be leaving this way.
Grissom's exit strategies are interrupted by a loud blast accompanied by deep rumbling. He and Sara hit the ground without a word and can do nothing but wait it out.
Outside, Catherine and Brass stop suddenly when they hear the detonation. "It came from inside the building again," Brass whispers, a little out of breath from their jog. Catherine holds her breath as she waits to see what the damage will be. There is a low thundering and the entire ground trembles. For a moment, it seems that all is well, until she hears a series of sharp crashes. The entire building shakes, then settles, then shakes again. Suddenly, it half collapses into the ground, sending up smoke and sprays of water. She blinks hard at the spectacle, and when her eyes open again, the building is partially underground.
"Grissom!" Brass barks into his walkie-talkie. "You'd better be alive in there!"
Catherine smiles at the laughter in Grissom's voice as he replies, "We're fine. A little shaken up, but we're okay."
Catherine lets Brass get the specifics from Grissom, satisfied that he and Sara are at least in no immediate danger. Time to get this thing solved, she thinks, and dials Warrick on his cell phone. When he answers, she hastily gives him instructions to the plant. "I need you both here now."
"Cath, we're still processing this scene," Warrick counters half-heartedly. Starting an argument with Catherine is usually a losing proposition.
"The officers will watch the scene and days will pick it up. We need you here." She's about to hang up but quickly adds, "And bring Archie with you."
She's about to place a call to Sofia when Greg comes trotting up. His exasperation is etched on his face. "Those cops are running all over my tire tracks! What's going on over here?" he asks petulantly.
"Another bomb," Catherine replies. Greg is suitably silenced. "Grissom and Sara are okay, but not in the greatest place," she says, anticipating his next question. Then she turns to him with curiosity. "You found tire tracks? From the dump vehicle?"
"It's gotta be the dump vehicle. It isn't one of ours and no one ever comes out here. I managed to get a cast of it before those guys trampled it up." Catherine's approving smile tells him that he's done well.
"Get it to the lab pronto. And keep your cell phone handy… we've got a lot to do tonight." She looks back to the crumbling building with her friends still trapped inside and presses her lips together. "Time to find Mr. Wright."