No Brakes!

[Jarwood]

Driving home from a car show today my brake pedal went to the floor. Nearly rear ended a woman in a Toyota!! After slamming the emergency brake down and throwing it in park....I ended up in the grass looking at her through the passenger side window. After getting out and checking things out, I found that the push rod that connects the brake pedal to the power booster came loose. I don't understand how a threaded part that pushes and not pulls came apart. Got it back together and drove home, but brake lights stayed on so I will have to adjust that.
I put the brake booster on about 6 months ago and have not had any problems until now. Can anybody explain why this may have happened. I sure don't want to experience that again!