Scariest shit ever!!

So i just got version 3.0 loaded on my radio, Installed a Turnigy 3d-h on my 450 pro. The set up was pretty easy with the help of youtube and friends. I took it to my friends house tonight so he could help me finish setting it up and get the gyro dialed in. Well after we got everything mechanically set up we took it for a test flight. First flight a couple feet up and gain needed to be dialed in, so we dialed the gain in. Then on the second flight my friend started to spool it up and my Devo8 with deviation 3.0 shut down and started going threw the bind process again!!! the heli lost signal and just sat on the ground at about 25% throttle at a limbo! I was freaking out, this was in the middle of the street with cars behind us and a Maserati backing out of his drive way about 15 feet from the spooling heli!! the driver didnt know we had a glitch and we where trying to think fast.
The only thing i could think of was getting a hammer and smashing it!! it had some nice sharp carbons on it. My friend thought quicker then me and got down on the ground, took his skinny arm and was able to grab the heli, it started to bounce and if he didnt act that quick it would have eventually tipped and did the death chicken dance and bounced off some cars. What a guy, thanks to him the heli may fly another day. So what happened? im running a Devo 802 rx no bind code. It was on 30mhz (but we where only a couple feet away and the radio totally powered down) the only thing i can think of is my tx batteries where to low? it only shows 2 bars down and is reading 4.5 volts. Is that to low?

Failsafe on the throttle channel?

Connect a servo to the receiver throttle channel, bind up, make sure throttle stick moves the servo then power down your radio. Safest way to check for a misconfigured failsafe.

Maybe test fly in a field or at an established club in future.