Other way around, he was run into the parking garage across the street. The video running around has him ambushing a cop on the east side of the El Centro school tower. I know from working in the area, the doors on that side of the school are usually locked by 8 to reduce access points. El Centro has already announced that everyone in the building got out and the shooter did not get access - which makes sense as the shooter would have had to run further to get to the next open door into the school than to run into the parking garage.
I’m no expert but the shooter seemed comfortable with his weapon and shooting someone up close without a second thought.
Military training?
Not to be disagreeable, but the video I was watching had a good view down the street between the white columned building and the red brick building, and the gunman appeared to run along the white columned building until he got to the corner of the bldg. and turned to the (viewer’s) left, putting him on the opposite side of the building from where he ambushed the officer. FOX was running this video from an amateur.
CNN had a video from another amateur that was almost directly across the street from the shooter and the SUV, that had the gunman in view until he turned the corner.
MSNBC had an amateur video of a person filming from the ground and caddy corner across the street from the white columned building and at the first corner that the gunman turned left at, then filmed him running along the white columned building. I can look up the street’s names, but you get the idea.
There is the possibility that after the gunman turned the second corner of the white columned building, he was chased back across the street into the parking garage.