I trained with one of those teams SRT group in the early 90's. Impressive folks looking for a needle in one hell of a big haystack.
Heck of a job. Trolling with a briefcase-sized radiation detector, hoping you never detect anything. God bless 'em if they ever do.
I think a dirty nuke is far more likely than this History Channel scenario.
And still it would be very disruptive. Thankfully, not as deadly.
Then I could worry about evacuating and that's why I keep my gas tank topped off.