<span>has been encoded during unusually high levels of stress</span>
Answer:
<h3>To act casual like nothing has happened.</h3>
Explanation:
In 'The Tell-Tale Heart', the narrator seat himself and the police officers in the room where the body is buried to indicate that nothing has happened and to avoid any suspicion from the officers.
When the police got called by his neighbor, the narrator hid the remains of the dead man beneath the floorboards and placed a chair above the dead man. The narrator says that he did that in order to avoid any suspicion when the police arrived. He sat on the chair and had a casual talk with the officers because he was sure that he won't get caught.
I'm not sure of the exact word you are looking for, but the general idea is that the federal law will always reign supreme if there is ever a conflict between the federal and state laws. Federal law is superior or higher-ranking or more preferable, etc.
Here is the exact phrasing from Article VI of the US Constitution: "This Constitution, and the laws of the United States which shall be made in pursuance thereof; and all treaties made, or which shall be made, under the authority of the United States, shall be the supreme law of the land; and the judges in every state shall be bound thereby, anything in the Constitution or laws of any State to the contrary notwithstanding."