I'm not sure how the facility is that you'll be going to, but at my facility, peer interviews are generally a lot of situational questions ("name a time when...") and then the typical, "why should we hire you?" and "why this area?" types of questions. The peer interview for the position I am taking in the NICU was different for the other jobs I've had peer interviews for. For this one, they were in the interview with the manager, and at the end, they were able to ask further questions if they needed to. For other peer interviews I've had, they were like what I already mentioned, and I also helped conduct a lot of peer interviews on my current unit.
The guide that we are given at my hospital to use in peer interviews asks questions like:
1. Name a time when you had to prioritize.
2. Name a time when you worked with a difficult employee and what you did to settle any disputes.(or something to that effect)
3. Name a time when you saw someone doing something wrong.
Etc. They really want to know how you work as a team and what you'll bring to the team if you're hired. How you handle conflict, your ethics, etc. You can Google "peer interview questions" and get many of these types questions! Good luck!