At home that night, Meredith tells Derek that she doesn't understand, and he tries to convince her that there isn't anything to understand -- he stared for 10 hours. He tries to change the subject and asks about her day, so she lets him know that she slept, ate a box of cereal, left messages for Izzie and tried and again failed to read Anna Karenina. He recognizes that she's trying to get back to talking about the tumor and she agrees, so he turns and seems really excited to start to explain it all to her. They go back and forth a bit and he tells her there was no path for him to cut, but when she asks why he has no answer. After thinking a moment, he jumps up, pulls the bed from the wall and then around so that Meredith is facing the space where her headboard just was, and pulls out a Sharpie to start drawing the spine and tumor on the wall. She points out that now he's lost his mind and she's really not wrong -- seriously, who does that, even if they are some surgical (or any other type of profession) god? But she smiles at him as he talks it out and draws on the wall, right underneath their framed marriage post-it.
It's now morning, which we can tell by the birds chirping, the pale light in the window, and the now multicolored and labeled drawing on the wall. Derek is going over how anything they propose could go horribly wrong, so Meredith finally suggests cutting the draining veins to expose the arteries. He tells her that they are thin and could burst, leaving him a quadrapalegic, so he might as well cut the cord. Meredith reminds him that he didn't cut the cord even though Isaac said he could, which, does he seriously need reminding of that? Why not try if the worst outcome is the one he was prepared for in the first place? She goes on that Derek stood there for 10 hours, knowing the Chief would stop him, and there must have been a reason. Sheer panic is not one she mentions, and so Derek thinks it over. There is quite an impressive amount of thinking (and pondering, and musing) in this episode.
Derek, Avery and Lexie are in a meeting with Richard, and it seems Derek told him he wants to just cut the cord. After Richard is assured that Isaac knows what that means, he reluctantly agrees and reminds Derek that it will only take 1-2 hours, and Hunt has the OR right afterward. In other words, it's a way to insure Derek gets out -- as if he thinks he has any control over what these doctors might actually do. He leaves, and Derek turns to his two residents and announces that they aren't cutting the cord. His mistake yesterday was making a plan when there can't be a plan, he has to just pick somewhere and cut. Lexie reminds him what happens if he hits an artery, etc. -- again, what happens is just what Isaac said they could do in the first place. Come on, guys! Think outside the box! Derek tells her that (finally): That Isaac wanted them to take the risk, and they have to try. He leaves, saying he'll see them in the OR.