25 C.F.R. § 900.186
No, it is optional. At the request of Indian tribes and tribal organizations, self-determination contracts shall include the following clauses to clarify the scope of FTCA coverage:
For purposes of Federal Tort Claims Act coverage, the contractor and its employees (including individuals performing personal services contracts with the contractor to provide health care services) are deemed to be employees of the Federal government while performing work under this contract. This status is not changed by the source of the funds used by the contractor to pay the employee's salary and benefits unless the employee receives additional compensation for performing covered services from anyone other than the contractor.
Under this contract, the contractor's employee may be required as a condition of employment to provide health services to non-IHS beneficiaries in order to meet contractual obligations. These services may be provided in either contractor or non-contractor facilities. The employee's status for Federal Tort Claims Act purposes is not affected.
25 C.F.R. § 900.186