The Who would like to know exactly who this "she" is.
The big block of bodies has been moved to the lab, where Emergency Backup David is put to work taking X-rays of it. We then transition to David the Dualistic Coroner telling Catherine, "Two sets of hands, two sets of feet, two skulls, two bodies. They both appear to be female. Jane Doe Bottom's curled up; Jane Doe Top's laid flat." Catherine points to the parallel tracks encircling Jane Doe Top's jaw and comments, "This looks like barbed wire." David thinks it's a dental appliance; Catherine prefers to think it's a torture device. Anyone who's had braces will tell you they're saying po-tay-to, po-tah-to here. David's all, "Do you think it's ritualistic?" What, the dental work? Catherine shrugs tiredly.
Just then, Gil skids in, a vapor cloud slowly dissolving in his wake. Displaying more enthusiasm than we've seen in at least two seasons, he burbles, "Hey! They told me you found two bodies covered in tar?" He's so excited about this, he's practically glowing.
The camera tastefully pulls away so Gil can have a moment to compose himself, and when we get back, he's busy asking Catherine how she plans to separate the bodies. Catherine's not sure -- she can't saw through the block without potentially damaging the bodies or the evidence, and the tar's not hard enough to chisel, but too sticky to peel. Gil's back to glowing again; he's also smirking gleefully, and rocking back and forth. Aww. It's so cute how he's all giddy in love. I wonder if he'll be sending a Valentine to the big block of tar? You were dug up, so big and black / And my heartbeat fell right off its track… He says he's got an idea, and Catherine's all, "Of course you do." Then she channels Ecklie and adds, "But last I checked, the backlog on Grasshopper, your adopted son number three, was about a hundred cases?" Gil gives her a look and issues a gentle smackdown: "You've been spending too much time with Ecklie. I'm off the clock. I came in early for this."
We then gear up for a science montage. You can tell because there's an electronic backbeat. Catherine and Gil are now wearing blue jumpsuits; she's sporting a drill and asking Gil, "Have you ever done this before?" "I usually try to keep my work life and my personal life separate," he replies. Oh, he does not either. He cheerfully says he hasn't, but adds, "I do know that tar becomes at brittle as glass at minus-200 degrees." Fahrenheit, Celsius, or Kelvin? You'd think a science show would be all into using actual units of measurement for these things. Anyway, what Gil then does is pour a lot of liquid nitrogen -- this is the stuff that freezes at 63 degrees K (or -210 Celsius, or -346 Fahrenheit), beloved of science teachers the world for its unparalleled ability to get students' attention with demonstrations like "Watch how I turn this banana into a hammer" and "Watch me shatter this penny." ["Those of us sadly familiar with its 'watch me burn off this wart' properties are not big fans. Heh." -- Sars]
Gil does neither of those crowd-pleasing experiments. Instead he and Catherine work together to drill some holes in the block, cap them with funnels, then pour in the liquid nitrogen. Afterward, Catherine's all, "Okay, Mr. Wizard," and Gil drops his tight science IN! HER! FACE! by tapping the block once and having it neatly fall into chunks. He and Catherine quickly chisel and wash the detritus off Jane Doe Bottom, and they comment that there's not much left of her but her clothing.