Indian law is at best marginally applicable, as the Indian government treats the Sentinelese as a de facto mostly-sovereign protectorate. The use of force in repelling unwanted visitors is one of the basic prerogatives of any nation, even a very tiny one, and the Sentinelese even follow a reasonably ethical use-of-force continuum, with shouts and then warning shots before only shooting to kill if someone doesn't leave on their own.