It wouldn't have been chloroform as if he fell unconscious he could hurt himself and C4 would be in the poo. I would need to see some scientific evidence that someone can have their brain "overloaded" and become unconscious from a telephone call. Can you link me to anything?
Exactly, as if Brown would risk saying some psycho babble down the phone and have him just collapse there, that's pretty risky. That's assuming it isn't all twaddle anyway!