At 1:04 into the clip... Gets real close. Looks like crew overrotated or rotated early... just waiting to break ground... Then second rotation wasn't (supposed) to be until positive rate.... But they didn have positive rate... initiated second rotation.... and they further decreased clearance.... Reminded me of a DC-8 rotation.... rotate to 8 (degrees) and wait.
It didn't look like a tail strike to me, but go look at the MX History for 850. Pay particular attention to the mx writeup concerning a windshear alert.