Carla says he can't do that, and we all know how much Walter enjoys being told what he can or can't do. "Shattering the wall between universes would rupture the fundamental constants of nature," she says, sounding just like my science teachers whenever we wanted to play god. Walter says that it's only a theory that crossing over would, you know, DESTROY THE UNIVERSE, and she says it's a good theory, which is why they've been lying to the military and saying it's impossible, and then she starts talking about how there has to be a line somewhere that they don't cross.
So he gets in a low blow about how he always considered her a scientist "despite [her] personal needs for religious claptrap" but he knows now he was wrong, and I don't think Walter is in a position to criticize someone making decisions based on "personal needs" right now.
She doesn't get mad, just quotes Oppenheimer's famous "I am become death, Destroyer of worlds" line at him, and he gets angrier, spitting about pursuing knowledge without morality and that she sounds like a "pious sanctimonious southern preacher," and she acknowledges going to church every Sunday but plays her three degrees in theoretical physics as a trump card to say he can't do this, because the amount of energy required to create a portal "will forever ruin both universes." Ruin like when you get mud on the carpet? Ruin like everyone in both universes is ripped apart molecule by molecule? She says he'll destroy the world for the sake of one life. "Some things are not ours to tamper with. Some things are God's," she says. Oh, doc. You had me, and then you lost me. Since STFU, Believers doesn't exist yet, Walter points out that his son is dying and he won't let that happen again: "There's only room for one god in this lab, and it's not yours."
He looks at the map, and points to Reiden Lake, by Albany. "It's perfect. The water will absorb the excess energy." He tells her he won't need her assistance any more today. She protests but he dismisses her with a curt "that will be all!" Hey, maybe you've still got time to catch a matinee of Back to the Future! I hear Eric Stoltz is intense.
Nope: she rats Walter out to Nina, who doesn't see what the big deal is, since Walter always goes off on "flights of fancy" but the design they'd need is decades beyond anything they could imagine. Carla tells Nina that Walter already has the design, and I'd like to point out that Carla saw an unhinged man with a contraption in the lab, which doesn't necessarily mean Walter has the design. Except of course he does, because Walter is so brilliant that he can accomplish something like traveling between universes on the first attempt with no problems, like all maiden voyages into the unknown. Anyway, Nina's concerned now, so she gets a cellphone the size of a fireplace log out of her purse and dials for Dr. Bell's room. They're too late! Walter's already at Lake Reiden with a vial of blue stuff!