My very tentative assessment is that for the British, the Indian Penal Code was a transition point from slavery to colonialism. A move away from "Look, we are not enslaving Africans! We are civilizing Indians and, this time, we have LAWS, proper codes." A lie. An alibi.

It arises, of course, from the 1857 Mutiny, but that Mutiny must also be seen within the long range of uprisings by the enslaved across the Caribbean. (If I had more brain space, I'd look at more legal history, but there's only enough space to do so much.)