A phrase ending in -i
(連用形) is an expression in its own right, not necessarily wrong. Of course, whether it is appropriate to use it in a certain situation is another question. Yes, it is "incomplete" as a sentence, but may not be "incomplete" in the way you think.
If you put it in English, it'd be like "life dwells in (each) a breath you breathe out, and", which would be felt quite truncated. But grammar-wise, it is merely another form in the verb's paradigm in Japanese, as if the difference between "I walk" and "I walked". Taking another example, A novel Brightness Falls from the Air by James Tiptree Jr. has a translated title 輝くもの天より堕ち, which is, by meaning, "brightness falls from the heavens, and", but grammatically comparable to "brightness's having fallen from the heavens" or "when brightness falls from the heavens". These English phrases are not "complete sentences" either, but are self-contained enough to be a title by themselves. It might sound like a brain twist because a piece of grammar, whose form is parallel to those English while carrying the Japanese meaning, is unavailable in English, but it is a basic device in Japanese.