There is a time gap, but let me first correct something. The call with Rachel wasn't formally ended. Your time frame is when the call was disconnected, which could have been at any time because Martin never hit the "end" button.
Even with that in mind, when Z ended his call he was at RVC as he stated during the walk through. He was probably 10 or 20 feet shy of RVC during the walk through, but from there it took him 30 seconds to reach where he said the confrontation happened near the "T". It seemed he was walking at a brisk pace in order to reach the spot where he said Martin came out of the darkness. So let's give him an extra 10 seconds for a slower pace, which brings us to 7:14:21. Then take into account he may have hesitated for a moment or 2 to think about where he wanted to be for police, or maybe just to contemplate the situation in general, or maybe he was fumbling with his phone. He also said he was still looking to see if he could spot him while he was walking. I'd say that might account for maybe an extra 15 seconds, bringing it to 7:14:36.
Now let's back track... The first 911 call at 7:16:11 was placed by Jenna. She testified that she decided to call when the 2 of them came scuffling by her patio and ended up on the ground between her house and John Good's. She also testified that from the time she made the decision to call 911, and the time the operator actually picked up, was around 30 seconds. That would place the 2 of them around 30-35 feet from the "T" at 7:15:41 She testified that she has no idea how much time elapsed between the time things started at the "T" and the time she decided to call 911. So roughly, that leaves a little over a minute from the time Zimmerman says the confrontation started, and when the 2 of them were about 10 -15 feet from the place where Martin would eventually be shot.
Now the day before Jenna testified, Jane (who lives north of her on the other side of the "T") took the witness stand and testified that from the time she heard the 2 voices that were in disagreement outside her window (when they first confronted each other at the "T") until she had turned her night light out and could see them on the ground in front of John's door, she estimates that a "couple of minutes" had passed. Now we know for a fact that it couldn't have been more than 2 minutes because according to Z's time line the confrontation started give or take, at around 7:14:21 and when the 911 operator picked up Jenna's call at 7:16:11, they were already on the ground, Zimmerman screaming for help, and John Good talking to them out his door. The reason I bring Jane's testimony up, is because she estimated "minutes", not "seconds" had elapsed from confrontation until Ground and pound.
Then there's Jeannee, in the corner house across from Jenna. She heard the first sounds coming from the area of the "T", looked but saw nothing, returned to her living room to watch TV, heard more sounds getting closer and went back to her patio door, saw nothing again, went back to watch TV, heard the yelling for help, them went back to her patio door and saw both them and John Good. Although she also could not estimate the time that had elapsed between the first noises toward the "T" and seeing them on the ground, I don't think a minute or 2 is unresonable...
Based on the time line and the witness testimony, I don't think your "run past Selene's house and then run back" theory is very plausible. If I had to take a guess of where that minute or so went, I would say most likely that once Martin punched him in the nose, he lost all concept of time and instead of him immediately stumbling 40 or 50 feet and being pinned on the ground in just a matter of seconds, he actually stumbled around for quite a bit longer than he remembers with Martin beating on him... He also may have taken a bit longer to start moving back toward his truck then he remembers after hanging up with police... Or it could be a combination of the 2... Either way, I don't see the unexplained loss of a minute or so as that big a deal here... After the experience Zimmerman went through that night, I can't see how anyone would expect a person to have total recall right down to the smallest most minute detail.
Now if there was say a 5 minute gap, then I would have been all over that right from the get-go.. But a minute, minute and a half... Just doesn't seem too significant, especially when you look at the timeline, George's story, and how they both fit with the witness testimony.
Now can you get back to the topic of analyzing the witnesses?