The nurse interrupts dinner -- the birth has begun. Dr. Clarkson is inexplicably already there (Edith must be a fast driver) and expresses his concerns to the family -- Sybil's ankles are swollen and she "seems muddled." Cora is worried, but Sir Philip dismisses Clarkson, and then takes him out into the hall to tell him to stop interfering. (They do also have a funny argument about the size of Lady Sybil's ankles. Or it would be funny if things were different.)
Somehow, Clarkson is still allowed to interfere. He walks into Sybil's room and with the power of the Lady Grantham behind him, orders a urine sample. Whatever test Clarkson did was quick, and he tells the family that he thinks that Sybil is at risk for eclampsia. (Wikipedia defines eclampsia as "an acute and life-threatening complication of pregnancy, characterized by the appearance of tonic-clonic seizures." Clearly, it's not good.) He wants to take Sybil to the hospital to perform a C-section. (Being English and in 1920, he does call it a Caesarean, though.)
Then there's a lot of yelling. Sir Philip tells everyone it's not safe to perform the surgery in a public hospital. And besides, he says she's not at risk for eclampsia. Robert, who does not to my knowledge hold a medical degree, wants to take Sir Philip's advice. Everyone else wants to ask Tom.
They do finally consult Sybil's husband and Tom almost agrees to follow Clarkson's lead. But when Tom asks if Clarkson swears he can save her, Clarkson says he can't swear to that. (A sane answer.) Sir Philip whines a bunch, asking Lord Grantham to step in. Robert simply adds to the hysteria. "Tom, Dr. Clarkson is not sure he can save her. Sir Philip is certain he can bring her through it with a living child. Isn't a certainty better than a doubt?" he says. Cora cries that they should have taken her to the hospital an hour ago. Sybil screams and they rush to her side.
Later, Mary comes downstairs to inform the men of the happy news -- it's a girl.
Before she goes to sleep, Sybil asks her mother to make sure she doesn't let Tom take another job as a chauffeur. Cora tells her youngest not to worry and that they will talk about it tomorrow.
In the hall, Sir Philip smugly congratulates himself on being master of the universe and urges Robert to forget about everything Clarkson and Cora said and just be happy that there's a healthy baby.
NEXT: Not so fast, Sir Philip