[Elecraft] Silly arrestor question

[Masleid, Michael A.]

I see that a coaxial line arrestor has a gas discharge tube between the center
conductor and the coaxial shield.  The other stuff, inductors, resistors, capacitors
are important, but not interesting during a lightning strike.  All of this stuff is in
a thick conductive box.

This may sound like a dumb question, but think about it.  How does the lightning
get out?  The walls are several skin depths thick.

There seems to be a ground lug on the outside of the box.  That would take care
of current on the outside of the coaxial cable well enough.

Wouldn't the voltage and current running between the center conductor and shield
have to reflect back up the coax, and then come back down the outside of the cable
to get to the ground lead?

Michael, AB9GV