While I am not recommending the "drugs" route for mtrad, I have the following question on this approach.
I thought, and someone please correct me if I'm wrong, that all you have to do is refuse to take the CDT, and you were automatically discharged, i.e. there is no requirement to either take, or admit (rightly or wrongly) to having taken drugs.
If this is correct:
Point 1: You haven't lied.
Point 2: You haven't actually taken drugs
If you tell a prospective employer that this was an action you undertook to leave the services, stated that you have no history of drug taking, stated you were willing to undertake any test you new employer required and even perhaps paid for some civy drug test giving you a clean bill of health, then would it really be a show stopper for a future career?
In a nutshell, my understanding is that you are dismissed for either failing a CDT, i.e. there is no doubt of your guilt, or refusing to take it, in which case there is no proof of your guilt, merely an assumption of it......
Standing by to be corrected by the more enlightened out there.