Chase runs out to join Leo's emergency, leaving Adam behind to man the phone lines with Spin and Bob while Bree is nowhere to be seen. At Leo's emergency, Adam, Bree and Chase enter together. Too much is unexplained.
Douglas' "Pencil Bazooka" is loaded backwards (Eraser tips out) and therefor harmless. In order to be lethal, or at least dangerous, (as the gag implies), the sharpened points of the pencils should be facing out.
Even though Chase says to Leo that Not Real Missions are not funny, he did previously do something like that to Bree in the Season 2 Episode "Prank You Very Much".
When Leo was hanging form the helicopter, he was only being hung inches towards the ground, so he could've just dropped down easily, no harm done.
The student body is conspicuously absent (with Donald's and Perry's absences are also quite noticeable).