*Sometimes* it is a very emotional kid who wants to show you how profoundly sad or upset he is feeling and used the words he *thinks* are appropriate. I am writing this because at the time, it is good to keep it low key and say "hmm, I think you want to say you are very sad, or you need some special time." You will be giving them words for their feelings and directing them to the appropriate route. You will also not be creating a situation where he says he will kill himself and gets loads of attention.
Again, it is important to follow up and see what is going on, but try not to overreact in the moment with the child.