(script static void ee_activate

sleep_until (crystals 00-04 destroyed or b_ex_p1_has_started) 1 minute
sleep_until (crystals 05-09 destroyed or b_ex_p1_has_started) 1 minute
sleep_until (crystals 10-14 destroyed or b_ex_p1_has_started) 1 minute
sleep_until (crystals 15-19 destroyed or b_ex_p1_has_started) 1 minute
sleep_until (crystals 20-24 destroyed or b_ex_p1_has_started) 1 minute
sleep_until (crystals 25-29 destroyed or b_ex_p1_has_started) 1 minute
sleep_until (crystals 30-34 destroyed or b_ex_p1_has_started) 1 minute

if (not b_ex_p1_has_started) set b_ee_unlocked true
)

Now, let's assume b_ex_p1_has_started is still false, and you've just finished destroying all 35 crystals. Wherever the script had got to in its execuion, it's going to continue within 1 minute, and at that point all remaining tests will be passed instantly, resulting in b_ee_unlocked being set to true; i.e. resulting in egg unlocking. That's how it works, right? So, I don't see the need for a 7 minute wait after crystal destruction is complete. The script seems to imply only 1 minute is sufficient (if I'm understanding its workings correctly).

Therefore I'm wondering if there was something bad about your test; the one where you said "I waited a few minutes and it didn't work". Like, perhaps you did something different in the waterfall area, which scuppered the egg despite b_ee_unlocked being true. In other words, the failure may've been nothing to do with the shortness of your wait, as long as it was at least a minute. So, perhaps it's worth checking into this again?

Eventually a tutorial from someone would be good, but it seems to me that a bit more investigation is in order first, in the interest of making the recipe as simple or quick as possible (I'd do some checking myself, but alas my 360 is bust). There's also the issue of understanding the b_ex_p1_has_started business better too, which could help; but this 7 minute wait is the biggest thing at the moment.