you could take a photo using different phone
if the app requires u to have a premium account (subscription) to watch videos it'll be difficult, depending upon the type of security it uses, its like you can't download a video from netflix (not easily)
if the app is simply streaming the videos without subscription you must find a (media url) might be something like this, https://cdn.xxxxxxxx/videos/002.mp4
or
https://cdn.xxxxxxxx/videos/002.m3u8
if you manage to fetch those media urls you could download the videos.