Yeah. It is a very important part. Here I present my recommendations: - Tell the positive case that their result is negative or inconclusive. - Smile (from far) while you quietly reach a telephone. - Tell'em you must go to the toilet. - Once safe in the bathroom, call the authorities - Since you have been in the vicinity report yourself and your guests to the authorities as well, or at least assume that they will arrest you. You have been a good citizen, but you guys are now a risk to the safety of others.