You do nothing, as you can be quite certain that any move on your part will cause the man to shoot.

The imposter keeps a close eye on Suxien as he holds his aim on you.  "I'm going to give you 'till the count of three before I start pulling the trigger!"

You close your eyes, certain that you are only moments away from a painful and disarming electrical blast, helpless to do anything but wait and see what will happen.

"One . . . two . . . thr--"  The man cries out as the pistol goes off, its electrical beam just missing you.  It hits the electronics panel just beside Suxie, causing half of the power grid to short out with a loud crackle.

You turn as the man drops the pistol, with Buzz biting and thrashing at his hand.  He slaps Buzz aside with an angry cry, then makes a dive for the pistol.  You:

Make a dive for the pistol.

Tackle him.