The ABCs of chain poison

[TLDunn213]

You start with C the catalyst 

Once that's in place you move on to 

B which by itself is harmless and will be broken down by the body into E which is excreted. But when C is present it  is turned into D which is deadly.

So to counteract D you take A the antidote. A turns D into E which is excreted but the reaction also turns A into B which then reacts with C forming more D. And so you are trapped by the chain poison.

Now the key to getting out of this is in E which can be collected from what you are excreting and then reacted with A to form F. Which can then be used to flush the C out of your system. And without C the B formed by naturalizing D with A just breaks down into E which is excreted and then you're free.

[Snypiuer]

WTF!?