CNN constructed a video timeline of the night Trayvon Martin was killed by Zimmerman. This timeline shows that medical personnel only had around 8 minutes to treat Zimmerman, and thus his injuries could not have been serious.
The gunshot was heard by a 9-11 caller at 7:16 pm, or 5 minutes since Zimmerman was telling the 9-11 dispatcher that "this guy looks like he's up to no good" at 7:11 pm.
Trayvon was talking to his girlfriend on his cell phone at 7:12. At 7:13, Zimmerman is still talking with the 9-11 dispatcher, who directs Zimmerman to stop following Trayvon. Zimmerman hangs up with 9-11 dispatcher at 7:15 and Trayvon is still talking with his girlfriend, when the lie goes dead at 7:16. At around 7:16, a neighbor calls 9-11, tells the dispatcher that she heard screams and then a gunshot.
The first officer arrived at the scene at 7:17 pm. The officer observed Zimmerman "bleeding from the nose and back of his head," according to the police report.
Law enforcement expert Alex Manning says you have around 2 minutes when not sure what happened. Looks like you have a window of perhaps 1-2 minutes for any confrontation because Trayvon's girlfriend heard Zimmerman ask Trayvon "What you doing around here?" before her phone call went dead at 7:16. At 7:30, a paramedic pronounces that Trayvon is dead.
Then Zimmerman is given first aid in the back seat of police car, but it is a matter of dispute as to when that happened. It is unknown at what time the paramedics arrived at the scene, how many paramedics were present, and whether paramedics treated Zimmerman and Trayvon at the same time. The police arrived at the station with Zimmerman at 7:52 pm, or 35 minutes after the first officer arrived at the crime scene. The "police station is a 15 minute drive away."
Manning says this timeline reveals to her that there was "little, if any, medical attention given to George Zimmerman. If the paramedics were with Trayvon Martin until 7:30 when they pronounced him dead," then the paramedics had around 8 minutes to do an assessment and give any medical treatment to Zimmerman between 7:30-7:38. She concluded: "He wasn't injured that bad."