Hi Sonny,
No there isn't a way to prevent it from capturing data and I really don't think there should be. Email could fail and then there would be no record of the submission, also for multi page forms we must keep track of the questions answered as they go from page to page.
If you really want to get rid of the data after the email is sent you could implement a custom Form Submission Event Handler that deletes its.
Best,
Joe