.22 handgun

Question
I have a discussion going on w/ my dad about a potentially dangerous situation in my husband's tech school.  Mark (husband) goes to a tech school in Pennsauken, NJ.  They have a drill for a gunman entering the school.  The class is supposed to go into the bathroom and lock the door.  I completely disagree w/ this drill.  From my childhood "background" growing up a USMC brat(my dad started his USMC career in Vietnam and ended up a Master Sgt.) plus he was a Phila. Highway Patrolman, I was always taught to never block yourself in, especially when there is a gun involved.  My dad says a .22 cannot go through a plain masterlock.  I say it's possible - not probable, but definitely possible.  What do you think?  Sorry about the long-winded explanation but there was info I thought you may have needed.  Thank you very much for your time and your opinion on this subject.  (I've only beat my dad at 2 things in my 32 years-I hope you can prove me right!)  

Answer
Mrs. Martin,

Thought it's been a long time since I've been there, It appears I grew up in your neck of the woods.

A tactical audit of the school and options would have to be done to determine an optimum course of action, but the plan is SOP for most schools (though usually with young children).

This is a tactical, rather than a mechanical consideration.  Miscreants who shoot up schools are not operators intent on particular targets.  They are cowards looking for targets of opportunity.  Being locked behind a heavy wooden door denies them visibility, and they are unlikely to enter where they can't see.  It denies them immediate access, so they are more likely to move on.

Except for the doorway, the builing is likely block, and therefore essentially bullet proof.  If gunfire was in the cards I would rather be out in the open than, e.g. trapped in a car, unless that car was armored, in which case I'd rather be in the car.

Hope you had nothing wagered on this.  Best to you.