I would suggest that they start screening their applicants but then they would run out of people who would blow themselves up for the cause when their superiors haven’t:

A WOULD-be suicide bomber fell down a flight of stairs and blew himself up as he headed out for an attack in Afghanistan, police say.
It was the second such incident in two days, with another man killing himself and three others on Tuesday when his bomb-filled waistcoat exploded as he was putting it on in the southern town of Lashkar Gah.

(via)