Opinions are my own...
My guess is false alarm caused by "scared" person. In any case, standing outside in large groups may not be best defensive tactic.
Can't say that I blame them.
'No evidence of any acts of violence.' USA TODAY headquarters evacuated after report of armed personThe newspaper's headquarters in suburban Virginia was evacuated; police said they were responding to reports of a man with a gun.www.usatoday.com
Someone probably wanted to get out of a meeting.
--- End of line (MCP)Police say report of a man with a weapon at USA TODAY headquarters was mistaken, after building evacuated
Reports are coming in that the bike was modified to create a backfire on purpose, just to create panic.And a motorcycle backfire caused mass panic in Times Square.