Recording voice while also playing video on iPad

Hi

We are hoping to use the iPad to coach early childhood teachers. This involves filming the teachers in the classroom, editing the film and then watching the edited film with the teacher. We need to record these coaching sessions. We like to audio record them on the iPad while also coaching using the video. Does anyone know if it is possible to run a voice recorder in the background while watching the video on the screen of the iPad. There are apps that say they will record in the background while another app is running, but we tried on iPhone and when a video played it shut down the voice recorder (we were using memo app).

Any advice is much appreciated

Thanks

Luke