If someone doesn't care if s/he lives or dies the only way to stop them is to kill them. Vide the kamikaze, the people who blow themselves up, those who flew into the Twin Towers, those who commit suicide by police, and others. IF they could be captured or found before plans are brought to completion they might be helped or at least segregated from doing harm. Of course, if someone believes that their death will serve a higher good (kamikaze, martyr, patriot), well, fanaticism will find a way even though it may be years later.

It's usually a waste of time to try to argue and change the mind of a True Believer unless you are very, very good.