Nicely done! Since Greg Nicol is leaving the building only at 6:13:25, this is 85 seconds later than the BC ESU post-action report indicated (namely 6:05-6:12) as the period BC ESU sniper left his post. So as long as this vague period was in the report, it is now even longer and vaguer.
Turning to the video itself rather than screenshot, my eyes may be fooling me, but I thought I saw Greg Nicol just behind that door for over four minutes before he did open the door. I tried to evidence it here. Anyone care to debunk or confirm this?