From an Ensemble Stars! visual novel type story, Victoria:
The character being spoken to just finished an unexpected ramble on the aesthetics of various ways of dying. Ending utterances in katakana is just the speaker's speech quirk.
I understand the quote to mean something along the lines of "You shouldn't go on talking about death like that, people will get worried", but don't really see how 死ぬ死ぬ connects to other elements in the sentence. What kind of construct is that and would it work with a different verb in 死ぬ's place?
Additionally, though I feel like the 言わないの constitutes some kind of an order or advice, I'm unsure of what would give it that meaning grammatically.