It's not suicide.

a. It's incompetence i.e. "But according to the instructions on the timer, I had 5 minutes to get away, not five seconds".
b. It's a lack of judgement i.e. "It's only 500 pounds of plastic explosive, I should be safe behind this gas truck".
c. They just don't run fast enough.

The really good news: 50% die while practicing their raids, and the other 50% die during execution of the attack. So we don't have many "experience" bad guys.