Back at the Labitrail, Gil is reviewing photos of the asphalt, looking for the groove that would indicate the snapped rod and thus back up Warrick's timeline and probable sequence of events. He looks giddy to be doing so. Meanwhile, a greatly subdued Liam is doodling at his desk while Sara paces back and forth, waiting for results on those swabs she took. Liam says, with some small amount of irritation and residual embarrassment, "I thought I told you I'd page you with the results." Sara replies that she prefers to wait. She stops pacing long enough to get Liam's attention and say seriously, "You're really good at what you do." Liam rolls his eyes a little and searches for a response, as Sara's watching his face intently, but before either one of them can say anything, there's a beep and her results spit out of a printer. Sara looks down, then says to Liam, "Sabotage," before watching her go. Liam looks thoughtful, and not too unhappy. Either he's finally realized the only person holding his inexperience in the field against him is him, or he's realized that he doesn't need to be a CSI in the field to have his colleagues' respect, or he's decided he's happiest being a lab tech. Any one of those three works, really.
Gil looks over the blueprints, sighing. As Sara walks in, Gil tells her excitedly, "I finally know the first action that initiated this skid. The right front tire came apart. When it blew, it left an indentation in the pavement...the treads from the right rear tire obscured it. The driver overcorrects, but since there's no more tire, all that force is displaced on the suspension system. The bolt snaps, the rod arm breaks, and the bus broadsides the Camaro." Sara pulls a Gil by reminding him that he's got the how, but he needs the why: "Why did the tire come apart in the first place?" Gil looks a little lost: "I don't know." Sara can barely contain her glee when she says, "I do. Chloroform inside the tire." She hands over the lab results for Gil. Gil responds, "Newton's Third...with a twist."
The CSIs are doing laps through the Labitrail, catching each other -- and, by extension, us -- up on what's going on: the chloroform was an act of premeditated sabotage, and whoever did it used chloroform because it destroys the elasticity of rubber. The goal: to find out how long it takes for this to happen, so the CSIs can figure out when the chloroform was introduced and go from there. Gil wants a big treadmill. Nicky: "For what?" Gil: "So we can exercise a bus." Performance anxiety, I tell you. Warrick is dispatched to get the treadmill and set up the bus. Sara goes off to deal with Trace. Gil, meanwhile, heads off to talk to Catherine and Brass, who are busy looking through the passengers' background files and trying to determine if any of the passengers had motive for sabotage -- or provided it for someone else. Nothing jumps out. Gil's suspicious of Eric's girlfriend Tracy; the three CSIs reason that since he was unhappy about her going to Vegas, since he was following the bus, and since he had access to chloroform, Eric may have sabotaged the tire in Barstow. Catherine's all, "Eric Kevlin was a nervous boyfriend, but he wasn't a criminal." Gil points out that Eric's got motive, access, and opportunity. Catherine runs off to check the Camaro for chloroform. After she leaves, Gil and Brass discuss the odds-on favorite among the sabotage suspects. Brass pins it on Maddox with, "He's been way too helpful." Brass just went on my list for that -- I like Maddox precisely because he's the kind of scrupulous, responsibility-taking small business owner who expects and enforces high standards. The man's done nothing but demonstrate that he takes the idea of personal and professional accountability seriously. Brass can go suck an egg for casting aspersions on Maddox.