The grenade does, in fact, do the trick, and the cloud of nanites dissipates entirely.<br/><br/>The door appears to be less of an intentional trap, and more of an accident; passing through it would likely be very hazardous to one's health. He might be able to reroute the power, and ground it, but it would certainly be tricky.<br/><br/>(Disable Device DC 30; fail by 5 or more (or attempt to pass through), and make a Ref DC 19 or take 38 electric damage (save halves))