Answer:emotion contagion
Step-by-step explanation:
This is situation where where an individual's emotion and behaviour has a direct influence on another individual's emotion and thus,it is being replicated.As the term connotes-emotional "contagion",there is a direct contact of emotions and they in some way synchronize,which brings about a replication of the emotions of the former (1st party) onto the latter(2nd party).It could also involve individuals to groups,vise-versa,groups to groups also.
Here in this scenario from the passage above,Caroline Her's nervous as a result of the shock being received by Nancy(who is obviously shocked&disappointed) and thus in turn,is shocked and also dissapointed that Nancy is kinda ignorant of Bill's past as he hadn't been fair in letting her know the truth about himself.She feels sober also as Nancy,and thus cannot continue the conversation with both of them(Bill&Nancy).