Amita is thrilled and wonders why he's not working on the paper. Alan cites "procrastination," and Charlie admits that he'd like to make it more relevant, but he's blocked. I know! I know! He can get pulled in on Don's case and use Brett's Circle of Remoras as a breakthrough in his studies! Amita thinks Charlie's idea is great as it is -- he just needs to buckle down to work. Ignoring her, Charlie dips a large rock in and out of the fish tank (where the beleaguered fish are now wondering why they're experiencing a tsunami. Clearly, I've seen Finding Nemo too many times) and mutters that he thinks he can tell Don the size of the Bathtub Murderer. How's he going to do that? By realizing, but not citing, Archimedes's third-century-B.C. discovery of fluid displacement. Eureka! See, Don thinks the killer was in the tub with his victim, which would have caused the water to rise. "So when the killer climbed out, the level fell," Alan says, warming to the idea. "By a very specific amount," Charlie finishes.
FBI. Megan examines the video for more clues, but hasn't found anything. They also still can't find Pete the camera guy. Megan then segues into talking about Colby being on the case. Don admits that until Colby gets reassigned, he (Don) needs another agent. Megan observes, "He must be looking at a pretty prime post. I mean, after what he did, he's considered a hero." Don has nothing to add to that, so luckily David walks with some photos of Andrea Barton he found in her apartment. They're old photos, which show Andrea what she looked like before she Nip/Tucked herself. I can't see that the chick in the pre-cut photos looks too different from the dead one, but she's looking crabby in all of them. When faced with the question of why Andrea wanted the transformative plastic surgery, Megan suggests that Andrea wanted to change who she was, based on any number of psychological reasons. David supposes she could have been hiding from her past. Don suggests they talk to the plastic surgeon and see what he knows.
Wide-eyed and awkward, Larry and Charlie arrive at Brett's house, equipped with their obvious objects of geekdom: a huge plastic funnel and a huge plastic graduated cylinder. Once inside, Charlie boggles so much at the actor's house, it would seem he's forgotten about the HUGE 1909 California Craftsman he calls home in a nice, treed neighborhood of Los Angeles. I seriously doubt there's much of a price difference between the two. Larry is hysterically, predictably, and philosophically unimpressed. "Measured against my recent accommodation -- the space station, the Zen hermitage -- it's a little excessive," Larry muses. The monastery didn't look tiny, but perhaps Larry is referring to his personal quarters there. "It's excessive by any means, Larry, but it's still awesome," Charlie observes. "It's emptiness itself -- this tempts me not!" Larry declares, moving on. It must be a testament to their acting ability that these two manage to delivery those lines with completely straight faces.