Deliver a sample of jet to Dr. Troy: when the Chosen One manufactures the cure, Dr. Troy gives them two vials of the antidote, one of which is passed on to Doc Johnson in Redding to cure the miners of their jet addiction. The Chosen is free to keep the second vial for themselves.
The antidote can be used on Myron. In this case, however, it will be consumed.
就算你没进行这个系列任务，在PMV Valdez号上的商人仍然可以买到解毒剂，who (curiously) carries almost no guns but loads of drugs, plus has several vials of jet antidote which are replenished if one buys them.