blood from both boys' brains. it is delicate. goodrich won't know until he gets close if he can separate it. goodrich and his team of 30 plus doctors and nurses have been prepping for months. now, they're putting the final touches on operating room number ten. >> i've never seen this sort of setup before. literally two operating tables. and two sort of setups for both boys here. >> the advantage to this is once you separate them, you just rotate the tables 90 degrees opposite. >> screens with brain images will guide the team, as well as anatomically exact models of the twins. >> is there a way to contextualize how much this makes your life easier? >> huge. there is no guesswork anymore. you physically have it right there. >> it is a game changer. >> it's pretty amazing. literally, cut here. >> the idea here is we know