Mentos and Diet Coke???

Just wondering but has any of you heard of dropping Mentos candy into a bottle of Diet Coke and an explosion will occur? I was at the store earlier and a man was buying the wrong kind of soda. The young cashier told him it had to be diet Coke to get a good explosion. Of course I had to butt in and ask what he was talking about. He told me what happens. He said you drop them in the bottle and run like hell. I'm wondering---> what happens if someone has Mentos in their mouth and they drink Diet Coke? Do they die?