Zinberg tries his best to convince Thackery to not undertake the operation case as he fears that if anything goes wrong, all the hospital staff will be in trouble.
However, Thackery didn't listen to him and decided to carry on with the operation as the concerned person was in bad shape and delaying the procedure could lead to his death in the season finale episode of "The Knick" titled "This Is All We Are."
As mentioned in the synopsis of the episode by TV.com, Thackery ignores Zinberg's advice at Mt. Sinai and undertakes a risky, alternative course of action while Cornelia confronts Henry about the family business.
Barrow's actions at the hospital construction site are called into question. Meanwhile, Gallinger ponders a job opportunity and Cleary steadfastly refuses to give up on Harriet.
In the previous episode titled "Do You Remember Moon Flower?" Thackery and Capt. Robertson's connection and how the doctor arrived at the Knick, were revealed.
The problems between Edwards and Gallinger came to a head after a medical-board hearing about Gallinger's vasectomies.
Later, Cleary and Harriet engaged in a joint business venture as Lucy shared memories with her father.
Barrow realised the rising costs of living well and Cornelia and Henry faced a family crisis.
There may be a possibility that Barrow set the fire in the previous episode that was discovered first by Captain Robertson. As Cornelia only shared her secrets with him, there is a possibility that Barrow got enraged and decided to set the building on fire.
Though there are no further hints, one of the major reasons behind Barrow's craziness would be that he is in dire need of money and thinking that insurance money may pay most of his debts, he might have decided to set the building on fire.
"The Knick" Season 2 season finale episode will air on 18 December, 2015.