If the account from a supposed Mr Willis, & strangely on the notorious 4Chan website, is true, then it is only one side of the incident report, in cases where there would be numerous accounts....
To be fair, in order to judge, one would need to find out from both sides in order to make informed decisions & judgments.
US Secret Service account:-
It was reported in the media that unnamed officials, as investigations are on-going, from the US Secret Service admitted to being informed of a suspicious person on a rooftop near Mr. Trump's rally site.
1) However, being a TOP security service
on American soil in peacetime, they had
NO authority to issue 'shoot to kill' orders upon civilians or suspects without evidence of threats.
2) There was NO confirmation from security service snipers with telescopes that the kid on the roof was carrying an object that it WAS a rifle. The telescopes may show up facial features, but the dark colored AR rifle could be anything else, perhaps a camera mounted with scopes that the paparazzi often used to take pics & sell to the media.
3) As Mr Trump was in a small
town that adores him, with even his pictures, posters & rally flags planted in their lawns, it would be a disaster to Mr. Trump's campaign & USA as a whole, should the kid who was on the rooftop turned out to be an innocent fan but shot dead.
4) Police were ordered to inspect the roof, but it was already too late as shots were fired....
Thus, as no confirmation by the security services snipers that the kid on roof was carrying a rifle, US Secret Service management, as well as risks to social order, the delay happened....
The supposed Security sniper Mr. Willis account, if true:-
1. While he claimed that he saw the assassin fiddling with his rifle, there were no other verification from other snipers.
2. He made a right call, to shoot the assassin the moment when shots were fired & chaos erupted at the rally site.
3. The standard bullet magazine of an AR15 carries 30 X 5.56mm bullets. It was reported that the assassin fired 8 rounds, which means he had 22 bullets left, which would have caused more deaths, even to the secret service agents covering Mr. Trump as such high velocity bullets would had ripped into their bullet proof vests, causing them to fall, & leave Mr. Trump a figurative sitting duck to those remaining bullets.
It was also reported in the media that the assassin bought 50 X 5.56mm from a gun store on the day of the event....
It was fortunate that Mr. Willis acted immediately. He had saved lives...if his account is true.