Does anyone thing he got on the drug after the first 2? Entirely possible. Maybe he figured that the enhanced hemoglobin levels in question wouldn't show up "so soon" on his third dip. Maybe he got cocky, and figured he could beat the system. Maybe he got tired from the altitude and thought he needed the drugs. Who knows?

I doubt he was thinking of hemoglobin counts, and he probably thought a pill not on the proscribed list was OK, or at least would slip through the cracks.