When viewing results of a test run on a iOS Native device, you can check the device logs to see the every testers' interactions with your app.
From your Run Results, click on a test. From there you can click on a step and view the screenshots of a particular tester. Scroll to the bottom of the window to find the logs.
You'll find three logs for each tester that captures activities regarding:
1. the startup activity of your app
2. the interactions during testing
3. the shutting down of your app
You can also find the logs from the Test view. Click on the History tab view results for a particular run, and follow the same steps as above.