He already tried earlier (from her words). The girl acted unexpectedly naively, inviting him again. But now you can assume that she is free too - because her unprincipled "friend" for some reason is not afraid of her absent boyfriend.
The first guy is a friend of the boyfriend of Agnie. Invited for a snack for brandy with cola. What is the usual practice in student hostels. The second guy - you can see, whose boyfriend (other ladies, from their words, are free). And, yes, this is Petersburg.