Eric Garcetti is Batman!
The witness to the entire event, a resident named Chris Cruse, didn't even recognize the good samaritan as Garcetti until it was resolved and Cruse asked his name.
Cruse posted his detail of the event on his Facebook page:
The nicest thing just happened.
I walked down my street to pick up some food, and came across a young guy laying on the sidewalk. His friend was yelling at him, slapping his face to wake up. The guy on the ground had a big gash and was bleeding out of his head. Not moving. I asked his friend if he was ok, but it was clear he needed help.
Right then, a black car pulled up on Silver Lake Blvd and a handsome businessman-looking guy rolled down the window. Asked if everything was ok. I told him this guy hit his head real bad. The car pulled over and 2 guys got out. They seemed to know exactly what to do. One brought a shirt and rolled it up and stuck it under the guy's head. Asked a bunch of questions. The other called the paramedics. The friend was worried that they'd be in trouble, and asked us to just leave them there. The handsome one said they work for the city, they can't just leave someone hurt on the ground. He hit his head, he needs to be checked out. The friend nodded ok.
Once the paramedics got there, they got the kid up and on a stretcher and into the ambulance. Seemed like he was in good hands. I was in awe that these two guys came in and handled this whole situation so quickly and solidly. As they headed back to the car, I stopped them and asked, "You said you work for the city, what's your name?" I wanted to know what city employee was being a civil servant and Good Samaritan even on a Saturday night. The guy shook my hand and said, "Eric Garcetti."