I was threatened ...plz hlp...?

i was threatened 3 days ago.. me and my brother in-law went to a friend of his house (a girl) and when we were there a two guys and a girl got there the guys where my brother in-laws friend's nephews ..we were ok at first but then the girl asked me for a smoke and i threw the pack at her .. my brother in-law asked me to apologize so i did but when the guy found out he threatened me with his ak-47 he didnt take it out but he went up to his car and warned me that he had it ...and since then i cant stop thinking about it.. im afraid my brother in-law has taken his friend to my house before and im worried she will remember were it is..what can i do what should i do..