"You cannot achieve the results that you are getting, at least in Russia, without doping," says Stepanov, who spent years working for Russia's supposed anti-doping agency. "You must dope. That is how it is done in Russia."
It seems to be an alarming trend elsewhere, too. In the cache of abnormal blood-level results obtained by German film-maker Hajo Seppelt and whose authenticity the IAAF does not dispute, there are 39 nationalities among the 225 athletes listed. Twenty-five Kenyans are named in a dossier of suspect blood data obtained between 2006 and 2008. By far the largest contingent, though, is Russia's at 58.
But it's the scale of the alleged state conspiracy uncovered by Seppelt that is truly eye-watering - that Russian doctors routinely authorise doping, athletes openly admit to it, a government edict has been issued to obstruct more rigorous controls and that a Kremlin-sponsored laboratory is apparently complicit in the cover-up.
When Seppelt took his findings to David Howman, director-general of the World Anti-Doping Agency in Montreal, the New Zealander simply shook his head in disbelief. It was the sheer cocktail of chicanery of which Russia was accused that most shocked him.
Yuliya Stepanova, the wife of rogue agent Vitaly and a fellow whistleblower, alleges in the video that the Russian anti-doping authority asked her for money for a drugs test and even to go to their Moscow headquarters to take it. Just about every aspect of such a request - that athletes should pay for testing, go to controls themselves, and not receive any arbitrary visits from inspectors - runs contrary to accepted international standards.
The first remark by Dick Pound, WADA's founding president, on being confronted with Seppelt's evidence was that "if made public, somebody must come up with an answer". Now, as Coe seeks to fend off Sergei Bubka in the race for the IAAF presidency, is that time.
The charge-sheet levelled against Russia would, until this past convulsive week, have been deemed inconceivable in 2014. Some of the more lurid contentions - that contaminated urine samples would be replaced with clean ones if a famous athlete risked exposure, that ordering erythropoietin (EPO) in Moscow has traditionally been as easy as calling up for a slice of margherita - are reminiscent of the worst East German excesses of old, not the brave new era of sophisticated random testing.
Five years ago, the athletics world would have mustered greater outrage for the accusations laid out in Seppert's report. The spectacle of discus thrower Evgenia Pecherina alleging "you can get anything the athlete wants" from Russian team doctors, or Stepanova's claim she was handed drugs by self-professed anti-doping crusader Sergei Portugalov - who only this year held a seminar on children's sport - should be sufficient to shake athletics out of their sense of amour propre for alleviating the drugs crisis. But it has lost its shock value.
The Russian scandal illustrates how long the shadow of the past is cast. Did nobody think to suggest that Valentin Baklakhnichev (who has dismissed the film as "lies") might not have immaculate credentials to serve as Russia's federation president (or IAAF treasurer, for that matter), given he was a Soviet coach during the 1980s?
That dark era, it appears, cannot be easily forgotten. Take a look at the women's track world records, across every distance from 100m to 3000m and not one of them has been broken in the past 21 years.
We have learned to regard these episodes as an integral element of athletics' bleak inheritance. But the latest Russian renegades have decided they should form no part of the present.
Their strength of feeling is reflected in their knowledge of the dire fate that could befall them. Russia remains a land where the outspoken can mysteriously be killed off in unexplained backstreet 'accidents', but whistleblowers like Yuliya Stepanova press on regardless. She recognises, now Seppelt's film has been screened, she will be forced to flee the country. But she considers it a price worth paying if it means her claims are heard.
Unfortunately for Russia, this is a story much too far-reaching to disappear obligingly. The web of alleged conspirators the film has put together encompasses every level of the state apparatus, right up to the top. Virtually all efforts to combat doping are financed and co-ordinated by the ministry of sport, where the incumbent minister, one Vitaly Mutko - who happens to hold a seat on Fifa's executive committee - is especially friendly with President Putin himself.
In 2010, an act of government was passed decreeing the transport and export of urine and blood samples should, at all time, be approved by state officers, also empowered to carry out inspections at the border. The politician who authorised it? Putin.
Seppelt believes his expose potentially represents the "biggest corruption scandal in the history of athletics". This is not a moment for hand-wringing, or delegating everything to an 'ethics committee', that ultimate sporting oxymoron.
In this battle, nothing less than Coe's own credibility, and that of a world he cherishes, is on the line.
