These video are from the time of the shooting, before the case blew up and became the politicized mess it’s become. They are both significant to the facts of what happened that led to the tragedy.
The first video shows a news report from the day after the shooting where an eyewitness says Zimmerman, on the ground as Martin was on top beating him, called help to him. Note : not just called out, but he says to the witness.
The second video shoots George Zimmerman reenacting what he says happened for the police. Zimmerman still has bandages on his head. His story appears to match what the witness told the news.
h/t to Kregg Janke for the heads up on the reenactment video