We present the results of our study of people's responses to unsafe scenarios with personal safety apps. Several such apps have been developed, offering features such as a location-sharing panic button. However, there is little research into how people might respond in different personal safety situations, and how such apps might contribute to their response. We performed a lab study with 30 participants and used semi-structured interviews to gather responses to a set of three increasingly risky scenarios, both before and after the installation of a personal safety app. From our results, participants stated that they would use mobile phones and personal safety apps most often to support “collective” responses, with calls to others for assistance. Further, while collective responses were often combined with “avoidance” or “protective” responses, when using a personal safety app, collective responses were less often combined with other reaction types. Overall, our results suggest some potential benefit from personal safety apps, though more study is required.