Although made at the operational level, the Marine training program instructor's decision to work a recruit to the point of permanent physical injury was a discretionary balancing of policy goals, and therefore not within the waiver of sovereign immunity in the Act.
http://media.ca1.uscourts.gov/pdf.opinions/17-2137P-01A.pdf
Since 2011. An occasional commonplacing of the U.S. Circuit Courts of Appeal.
Neither an authoritative statement of the law nor legal advice. Quick work.