from a data standpoint you just cannot say "this mile was covered in 5:xx" because the data source does not capture that information right now.
The estimated 5k PR shown on his profile linked to that activity before it was deleted. I believe those are based on elapsed time and it was 16-something, so he was supposedly running sub-6 continuously for at least 3 miles.[/quote]
Here's the duplicate of that run, I think. At least 5 consecutive sub-6 miles according to that, with a Strava-estimated 16:56 5K and 5:05 mile in there somewhere.