Doggett, Dickhead, Tubby, and Lyle pour themselves into the subway tunnel and make a lot of noise about how hot it is. Tubby explains that, with the power down, the air conditioner is also down, and there's very little ventilation in the tunnels. So it's hot. Very, very hot. Stifling, even. Extremely warm. Got it? As they trudge down the darkened tunnel, Lyle makes some comment about how they're suffering just so that all of Boston can "get home to watch Survivor II," and if the folks at 1013 have done away with the date stamps in order to keep the chronology of this season hazy, then I suggest they also try to read the scripts, because that just totally gave away when this episode takes place. Survivor II debuted after the Super Bowl, January 28. If Scully was pregnant the night after Mulder was abducted, which, as we learned last week, was in May, then she is eight months pregnant. At least. I know Chris Carter thinks he's smarter than the rest of us, but, dude. We can count to eight. Jesus.

The group wanders through the tunnel for, like, the rest of my life. Grousing, walking, grousing, walking, yada. They sweat and walk and walk and sweat. Tubby splashes through a puddle -- which, unnoticed by any of them, glows an iridescent green.

Scully checks in with the crew in the tunnel. Doggett's giving her the 411, when Tubby starts yelping behind him. Something is "burning" his neck. The brainaics manage to figure out that something must have dripped onto him, burning him. Or something. Tubby, in the midst of yelping about his neck, manages to squeak out a bit of exposition: the tunnel they're in is adjacent to the Harbor, and was contructed during "the big dig," which my Bostonian expert assures me is an actual event. Scully directs Lyle to send her a sample of a nearby puddle, assuming that whatever dripped onto Tubby also dripped into said puddle. Lyle makes a crankypants face, but does it, dropping the sample into a handheld tox-screener, which transmits the results to Scully's computer upstairs. Cool. And handy! Yackety-smackety, the sample is basically ocean water. Scully sighs, and says she has to make some calls. Karas, in the background, barks that she has four hours left! Scully purses her lips.

Back in the tunnel, we learn that: it's hot. So hot. So very hot. Super-duper hot. Heatastic. Like an oven. After more boring macho posturing from Dickhead, and several interminable shots of the freaking tunnel, the group comes to a fork in the road. Scully tells Doggett that they're looking at a line that is no longer in use. Behind her, Karas barks that the line is obsolete. Cram it, Bossy McBoston. Scully informs Doggett that he's about a mile from where the original incident occurred. Karas: You're wasting valuable time, you stupid redheaded woman! Damn you! Damn you to hell! TO! HELL! Scully: Whatever.