Well, if you don't start the bcp on the day you are supposed to, the ovulation process may have started already. You likely are not going to get pregnant, as the sperm will die long before ovulation, but you do have the risk until the next cycle begins. If you have to miss a pill, do not have it be the first one.

So don't worry right now, but be careful in the near future.

It takes two people to have sex, but if they have already discussed all of this, then I am sure it was already decided for him to pull out. That is most likely what she is angry about. But I don't know.

Anyway, I would go today and get the morning after pill. It is better safe than sorry and if you don't want a baby right now then go and take that. But, do it soon.
And in the future, wear condoms with the birth control. You can get pregnant from precum anyway, so even if he didn't "bust" in you, you still could get pregnant.

Taking bc pills will not terminate a pregnancy however if you are pregnant and continue taking them you can mega harm your baby

Even if it was decided for him to pull out it doesnt matter unprotected sex is unprotected sex and she culd have gotten pregnant anytime during the process... I got pregnant the day my period started

Its been a week its too late for the pill

Actually, my doctor told me that the morning after pill will not harm a pregnancy that already exists. All it does is stop you from ovulating or keep you from ovulating so that if you haven't already conceived, you wont.
And yes, I agree that unprotected sex is unprotected sex and she could have gotten pregnant from precum at any time during the intercourse. But, I also understand that when you are trusting your partner not to finish inside of you, then I would be royally pissed if he did too! Even though with no other source of birth control, it may not even matter.
I am on the pill, but also use condoms as much as possible. If I do have sex without a condom I do not let him "finish" in me either. It is just unnecessary risk, but ideally I shouldn't be having sex without condoms anyway.

Does anyone know when you are most susceptible to becoming pregnant like how long before your period or w/e

It depends on your body. Most people will tell you 14 days, because that is supposedly when the average woman ovulates, but that only matters if you ovulate then. It depends on when you ovulate, so no one can really answer that for you.