A rock skittering onto your line, a root still greasy with the morning dew, a camera flash sparking from the trackside, in the pulse-pounding, high-stakes world of downhill, the smallest variable can make all the difference.
With just three minutes to lay down your best, there simply is no room for error in this cut-throat world. Those that can find the hair's breadth of space are beatified as heroes, those the other side of that line can only slink back to the pits to stew for a fortnight until they do battle again.
The closest winning margin for the past few years has been Leogang 2015 - 0.045 seconds. Gwin's chainless run just denied Connor Fearon of his first ever World Cup win. To put that into context, Usain Bolt won the gold medal in the 100m sprint in the Beijing Olympics by 0.2, a four times greater margin in an event that lasts only 10 seconds.
In fact, ten races in the last four years have been won by less than a second, with the average margin coming in at around 1.7 seconds (although this could be a bit skewed by anomalies such as Gee's bog run in Cairns, which gave a huge margin 4.2 seconds in freak conditions).
In the men's field it's as tight as Troy Brosnan's trousers week-in, week-out. You can't help but admire the level that all these guys are pushing to just to stay in touch.
But what affects the winning margin? Where are the patterns? And does the conventional wisdom that easier tracks produce closer winning margins stand up to scrutiny?
Yes and no. Leogang and Lenzerheide may be dominating the top three spaces but Vallnord, Meribel and Mont Sainte Anne all follow closely behind. In fact, all four of the most recent races in Quebec have been won by a smaller than average margin. Bear in mind this is the longest, fastest and one of the toughest tracks on the circuit, and it's been heavily weather affected in recent times. The average winning margin here is half of that of Leogang since 2013.
Down the other end of things, Gee's stellar performance in the Cairns monsoon muck gives him the biggest winning margin of the past few years but it's in the mix with Lourdes, Windham, Fort Bill and Leogang. There really isn't a strong pattern here...
It's not just about first and second though, there's a whole podium to fight for.
Looking at the numbers, on average you need to be within four seconds of the winning time to get on the box. Tight at the top.
Meribel '14 crops up again as a tight one with just over a second separating Sam Hill in first and Gee in fifth. The steep, wide-open slopes in France produced an absolute stormer of a race. With so many variables, it's tough to say where this came from but we've been wondering if it was to do with it being a new track that had everyone working out their own lines and exploits. Answers on a postcard please...
From then on, it's a similar story. Leogang and Lenzerheide are up there but so are Vallnord and Mont Sainte Anne. Down at the bottom, Leogang and Cairns occupy the same space as Lourdes, Val Di Sole and Vallnord and there are also entries from Lenzerheide and Windham in the bottom half.
So what are we getting at here? Well, yes, generally it seems that the closest races are happening on the 'bike park style' tracks, but it's certainly no rule. In a sport where so much can go wrong, and so much can go right, at any moment, there's far more that goes into close racing than race tracks.