Google street view, from the same angle as the video
Then turning Google street view 180 degrees to the house across the street (420 Geraldine St) -- looks like the video was taken from a second floor window on the side of the house. The multi-trunked tree is seen on the left.
In that video from second floor window, a stub of the severely pruned tree in front of the house is briefly seen at 0:11, and the multi-trunked tree is also seen on the right at 0:11 -- the video at 0:11 seconds...
Zooming in on the tree in the video with four trunks (not four human legs)...
The same tree seen from the opposite side in Google street view (a different angle, so the spacing of the tree trunks differs appropriately)...
My conclusion is that the dark lines are tree trunks, not human legs, and not two men watching the shooter enter the school from across the street.
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