Nothing is much known about Tammy, but it's likely that Eli saved her from Jacob, as he states that he trusted her. Since they have been friends, despite the War against the Cult had gotten them into arguments.
Far Cry 5Edit
The World Is WeakEdit
When Eli and Wheaty returns to The Wolf Den with the Deputy , she says that they can't trust anyone who Jacob had manipulated to "sacrifice the weak", to which Eli replies that he trusted her, and he was right and they need the Deputy to fight Jacob.