engineer in flex is hectic.
engineer is the buffer guy that cushion all problems from the manager. requires high analytical skills, high management skills, higher tai-chi skill and not so high technical skills. everyday is war. except when you dont have project. survive flex, u can survive anywhere. good for those who loves challenge.

show your determination and energy. and problem solving skills.
dont tell your manager that u dont plan to stay long for your first job.

what product? different flex different product. prepare some university's technical knowledge. (i.e. if the product is mobile phone, they'll ask whats a psuedocode, describe pll etc).