meh. Occom's Razor. The JV team was on security because the Speaker wasn't there, the Pelosi's are *expletive deleted*it to their staff so they probably have crap employee's on the JV team, and the principal's probably bypass security protocols on the regular because "important People" always feel like the annoying parts of physical security don't apply to them.
Add that up and crazy can walk in and find Paul, and get a couple swings in before anyone responds to the alarm.