@westcoastbestcoast said:
I thought that the sentence that contains the condition in which the company allows Ann to leave was a bi-conditional and therefore we could get the contrapositive of the bi-conditional by negating both terms. ...
Oh my gosh, it all makes sense now! So as long as there is F1 before G1 G2 can go either before or after F2!
Thank you so much for your kind and detailed explanation :)