“Really dont know why secret service did not open fore on him well away from trump when they first saw him.”
They gave to make a sometimes difficult judgement call. Every round fired, especially into the air, may find an unintended target. Presumably, somebody made an instant evaluation of the perceived threat and didn’t fire. I was so impressed by the footage of the agents around Reagan after he was shot. Machine guns out, none of them fired.
You have no time to think about secondary targets when time is of the essence and the life of President Trump is at stake. If you can’t pull the trigger, you can’t do the job. Go find a desk job.