Three = every single one?
Keep in mind that three of the four people in the group they were supposedly testing had no idea what was happening. It was only obvious to the viewers because the camera lingered on the items. Most new visitors are going to be focused on the food. A test that depends on hyper awareness of the test subject seems pretty pointless.
And does it make sense for Alex to turn his back on people they were supposedly testing? The hand signal from Gareth seemed to execute their "no hostages" plan. The way Alex was trying to plead with his own people led me to believe this was their well established policy in dealing with "terrorists".
The people outside the fence could have easily been on patrol, which would make the unlocked fences easier to justify. There were several minutes of gunfire before they needed to be in their final positions.
Only Mary and Gareth didn't have items and Gareth held back to give the signal, Alex and the three others each had one thing prominently displayed. What the heck would a guy be doing at lunch with riot gear on? Oh, it's Atlanta, let's put the poncho on, I'm getting cold. Hey, I was thinking about camping this weekend at Stone mountain, let's get my backpack ready here at this table. If they are just lounging there playing with these items, they sure got ready with guns in a split second.
Again, with all of that firepower, why go through this process at all? This wasn't a terrorist policy where they got invaded. It was already coordinated. The people behind the fence were on patrol?Are you trying to say that they didn't have that snare completely setup already? They were there to stop them from going further. The snipers guided them specifically to that location where they were at the fence. Also, it wasn't several minutes of gunfire. Rick's crew bolted as soon as Alex was shot and ran through the a couple alley ways and buildings. If that took more than 30-45 seconds, I would be shocked. Why did they all go right to that fence where the rail car was, why not go inside the fence since the shots were in a completely different area? I'll tell you why, it was already setup for them to be waiting there.