I just got Lenovo yoga 2 and can not find silent mode (power button offers just - power of, resrt and aeroplane mode). There must be silnt mode to turn every sound off... Big thanks!
Most phones go in silent mode when you just press volume down and silence it to the end. After hitting lowest volume, pressing it again should put it in vibrate only mode, and pressing it again will put it in silent mode. I'm not sure if Lenovo phones have that implemented but most other OEMs have it implemented.