Hearing about Ellison from sources at the hospital, Sandburg, a graduate student in Anthropology, shows up uninvited to help out.
Sandburg believes that Ellison is the living embodiment of his thesis topic, a Sentinel.
Theorizing that Ellison's extended stay in the jungle activated his latent abilities, Sandburg wants to study Ellison for his research.
Ellison at first angrily rejects Sandburg's help, but soon rethinks.
Sandburg has warned him about the 'zone out factor', when a Sentinel gets too tuned in to one sense to the exclusion of others.