Yeah, he knows the dozens of secret service agents would never let him put himself in harms way but would look great for the cameras of him 'trying'.
It is fun to visualize Bullwinkle's idea... Trump kicking down the door with a complete circle of agents opening fire all at the same time.
I'm just picturing an armored vehicle crashing into the school, running over the shooter, a Navy Seal getting out, opening the back door, Trump stepping out, facing the children and telling them "Ok, ok, no need to thank me, I just did my duty".