I know we've walked out of Fantasmic into the fireworks show, just as it was beginning. But I don't remember how long it was between shows during that trip. If I remember correctly, Fanstasmic runs about 22 minutes long. So, you'll have only 8 minutes to get out of the theatre and back to the fireworks show. I don't think it would be possible with a dining package. The dining package gets you into the centre section of the theatre, and to be able to catch the fireworks show, you're going to want to be near the exit, so you can basically be first out of the theatre. If you're first out of the theatre, and don't mind being at the back of the crowd for the fireworks, then it might be possible, but not guaranteed.