by cvoinescu » Sun Jul 07, 2013 4:26 pm
Yes, there is. If you interrupt the path from the negative terminal of the laser to ground, you'll have the high voltage present there. I'm sure your SPDT is not rated for tens of thousands of volts. For the same reason, it's dangerous -- the connection to ground should be permanent.
However, there's nothing that prevents you from having two ammeters in series. Digital ones usually want one of the terminals to be ground; analog ones don't care, so you can connect the analog one nearer the laser.