Is it safe to take plan b twice in one cycle?

Asking for My friend.

Here is the story...

Currently she is a bit loose after breaking up with her ex of 8 years (just before Christmas she caught him cheating, in bed with her heavily pregnant cousin, yes now the baby is born the DNA proved he is the dad) anyway she has been drinking out in the clubs with friends every weekend and more or less sleeping with any guy that looks her way.

She took plan b just over 2 weeks ago and she is waiting for a birth control appointment (she isn’t on anything as she was trying for a baby before she found her ex was cheating) well she had sex twice last night and the second time the condom split. The guy was decent enough to buy her plan b on the way dropping her home.

We are wondering Is it safe for her to take it again so soon after the first one she took when she hasn’t had her period yet?