The percentage is the game's most clinical statement of Deadman's composition, the specific measure of how much of him came from people who were already gone. 70% is most of a person — most of his mass, most of his biological substrate, most of the material that the world encounters when it encounters him. The 30% that was not harvested is where the game declines to complete the accounting, leaving open what Deadman's origin actually was in its entirety.

The warning he gives Sam in this session is the warning of someone who has studied the situation from the outside and can see what Sam cannot see from inside it. Deadman's analytical function — the Bridges doctor who assesses and reports — is the role his nature allows him. He cannot go into the field. He cannot be a porter. What he can do is think clearly about what the field is doing to the people in it, which is the specific gift that 70% cadaver composition and a life of studied marginalization has produced.