When the HYDRA Uprising began, Agent Barbour was one of the few agents that Victoria Hand knew was not a HYDRA sleeper agent. He witnessed her give the order to kill Phil Coulson's team and John Garrett when they arrived on the Bus to the Hub, since she believed they were traitors.
As everyone in the Hub was being corralled in order to determine their allegiance, Barbour reported to Hand that Agents Jemma Simmons and Antoine Triplett were not accounted for. Hand told him and Agent Shaw to keep searching. When they were found, Barbour was one of three agents who held them at gunpoint until Hand arrived. He witnessed the two agents pass her test of loyalty.
When the kill-order guards failed, Barbour reported this to Hand.
- S.H.I.E.L.D. (First Incarnation)