Do you think you are going to pass your med for a flight license with that load?
Well, obviously either Halliday did so, that or he did his medical before he was on all of those meds, or he just stopped taking them a while before doing his urinalysis for the medical/Cat4/Cat3/whatever category he got for his license. IF he got his license in Canada while with the Blue Jays, the Cat4/rec permit doesn't require a urinalysis, so there's that possibility too.
Of course not, but people are known to cheat such things - the majority if not ALL of those drugs after a week of being off them aren't detectable with a typical blood/urinalysis, unless a hair sample is taken and analyzed. I know my mother's urine screens she had to do, if she didn't take any morphine for 3 or 4 days, it wouldn't show up in the testing despite her taking it daily for months beforehand. Also, if Halliday got his license in Canada when he was up here, if he just did a rec permit then upgraded it, they don't even take a urine screen, it's just a "I declare" sort of BS thing IIRC. Or perhaps Doc got his license before he was prescribed all that crap.
Here in Canada the use of opioids by prescription is one of the highest in the world. RCMP stats say that up to 1 in 10 of every car you pass driving has someone operating it who is prescribed some sort of painkiller, along with probably lots of other meds. Most of these people don't crash their cars. I"m not saying there isn't impairment, of course there is, but after being on opioids/etc for long term, most people's systems build up a tolerance pretty quickly (this is one of the big problems with painkillers), and the amount of impairment drops significantly.
The RCMP/etc here in Canada have a new device they just started using since MJ was legalized here, the Drager Drug Test 5000 (sounds like a Robocop movie name). It can detect pretty much every opioid out there, along the the weed, just from oral swabs/tests at the roadside. I'll find the link I read on the data, but they were pretty stunned during trial runs with it, when they realized that 10% or more of the drivers they tested one day, were all testing positive for various prescription painkillers the device detects, and even more surprised that the vast, VAST majority of those with a positive result, were easily passing the typical roadside impairment tests they perform, such as the counting backwards/walking heel toe/etc. Again, I don't disagree that there is obviously going to be some sort of impairment, but for long term users like Halliday likely was, it's not like they are stumbling babbling drunks who are easy to spot.
Witnesses say he was jerking around when he crashed - crashing while doing stunts like he supposedly was could have happened to him with or without all those drugs in his system, ie just laying it off on the test results probably isn't the only, or even main reason he crashed. Again, IMO there would be some level of impairment due to all the different drugs he was on, but also IMO if any of us ran into him 20 minutes before his flight, I'd highly, highly doubt any of us would think he was whacked out on the junk.