[PapaBear3625]

Basically, he could have arrived with a baseball bat....whacked the first guard....taken his weapons....and done all the damage from that point on.

Or, less conspicuous than a bat, had a glass dagger

which would have gone right through the metal detectors. Walk up to a guard from behind, slip the dagger into a kidney or the throat, take the guard's gun.

[zeugma]

Obsidian works just as well.