The Sandbox was a S.H.I.E.L.D. research facility located in Africa, specializing in the handling and study of hazardous materials. It was considered a very desirable assignment by students at the S.H.I.E.L.D. Academy of Science and Technology.
Felix Blake contacted Coulson from the Sandbox and explained to him that, as S.H.I.E.L.D. had no record of anything like the virus, it was imperative that the helmet arrived at the Sandbox without incident, as it would be needed in case of pandemic. For that reason, S.H.I.E.L.D. Headquarters ordered Coulson to dump any infected cargo, an order that would include Jemma Simmons. Coulson, unwilling to follow the order, feigned a bad connection to cut off and ignore further calls from S.H.I.E.L.D.
Coulson arrived at the Sandbox, and handed the Chitauri Helmet to the agents waiting for it. Blake confronted Coulson for ignoring a direct order, stating that whatever happened to him in the events surrounding the Battle of New York did not gave him a license to disobey a direct order from Headquarters. Blake warned him that he if continued to do these kind of things, his team might be taken away from him. As Coulson answered the warning with a taunt, Blake noted how much Coulson had changed.
Imprisonment of Donnie Gill
Donnie Gill was imprisoned at the Sandbox in order to be watched following his creation of a large scale Atmospheric Moisture Freezing Device that caused a super storm over the S.H.I.E.L.D. Academy of Science and Technology. The incident cost the life of Seth Dormer, a fellow student and accomplice in the creation of the device, and accidentally gave Gill the power to freeze objects around him.
Scientists at the base realized he had these powers, though limited, and he was taught to control and amplify his powers. Secretly, Gill was also brainwashed by HYDRA scientists embedded at the base in order to act as a sleeper operative against S.H.I.E.L.D. in case of need.
- In the comics, The Sandbox is one of Nick Fury's secret bases, located in Sudan and used as staging area for activities in North Africa and the Middle East.