Ignores Silent mode setting,

Opened this app for the first time while at work. I flip thru the welcome slides then click Lets Go. Suddenly a loud voice starts blaring from my cube. My phone is in Silent mode! I frantically look for the Stop play button but see nothing! I had to jack the volume to zero and then search and search for how to stop this voice!
Im deleting this app until the creators can regain my confidence that they know what good UX is. What I experienced was not!!

The Teaman about hibooks - amazing audiobooks