Nope, you just take out the armed guards first and then proceed to the main targets. The armed guards will have been lulled into a sense of complacency. The emergency responders really don't respond (the cops sat outside Columbine for hours after the threat was over).
Get a grip.
Your comment made me think of the movie Die Hard and the armed guards did get it your right.
How 'bout making sure your knowledge of standard reaction protocols isn't over ten years out of date before you offer advice to those of us who are keeping up.
Columbine was 1999.
And "take out the armed guards first?" You watch too many movies. That statement is as asinine as Steve Martin's old joke "first, get a million dollars....etc"