By the way, the easiest way to launch from your hand is do this:
1. Hold the drone up by grasping if with fingers and thumb from underneath, below line of propellers.
2. With the left hand, preferably with the controller on a tether from around your neck, pull the two sticks down and in, to start the motors idling.
3. Then just toss the drone up a little and the engines will rev and the drone will hover till you take off and fly away.
This way you can avoid any underground, under concrete, interference from metal.