Resurrectionist
Dr. Rock compares the graverobbers Fallon and Broom with resurrectionists. They provide the doctor with the dead bodies which he needs to continue his research. The doctor knows they are below his stature but for the sake of his vainglorious attitude, he indicates them with this term. It is an ironical way of saying that those graverobbers aren't actually the pious resurrectionists. They are doing this only for some money.
Doctor's Attitude
Doctor Rock's attitude is somehow ironical in the drama. He projects himself as a medical professional who has a dominant zeal to enlighten his field. Medical research is a sacred work for him and he thinks that he is like a God in his field. His dialogues and conversation make it clear to the readers that Dylan Thomas is actually satirizing the thinking behind such idolatry.
Christianity
There is an explicit reference to dogmatic Christian beliefs in the drama. But the reference doesn't sound that sacred at all. In fact Dr. Rock compares the graverobbers with the holy resurrectionists. In this way the dramatist mocks Christianity and the whole idea of resurrection suffering badly in the age of materialism and capitalism.
The Trial
When Fallon and Broom are caught for their heinous work, the doctor is unharmed. Though his reputation is destroyed, he is still above the grip of mundane law. In this way Thomas hints that a misdeed is seen as a crime when it is committed by a person belonging from the lower section of the society. In the case of the doctor, it's just a folly.
Human Body
There is an ironical reference to the human body in the drama. After death a human is treated just as a product of business in the play. The doctor finds it comfortable to continue his research when he gets a fresh human body. The decomposed bodies are of no work to him. It is true that to prosper in medical research one has to be solid as rock at heart. Still, the treatment of the bodies in the play is ironical and it strikes the consciousness of a reader deeply.
