Sheldon Brewer was a loyal employee working at the Ouroboros Corporation.
Biography
Chapter 10.3.3
Brenda Utely revealed to Zion operatives Sheldon Brewer, who works at Ouroboros, is said to have access to a virtual map of his company's internal network.
Chapter 10.3.4
By the time of the next chapter, it was revealed that this map was implanted surgically into his pod-form's brain, without him knowing it. Although it was difficult to extract due to being in the real world, but was overcome with a red pill trace program and the co-ordination with a hovercraft.