There is no way anything that happened would have affected the power plug. He probably meant, and that's my best guess, that the surge/spike had caused some of the controls to shutdown the section that is powered by that particular plug. I don't have enough info to guess why then, whatever tripped has been reset, you will have to ask him to explain the possibilities to you in plan language.
Although I predicted there would be no damages to the expensive power amp section and the power supplies for reasons I explained, I did anticipate they may have to replace one or more electronic parts or modules that may have something to do with the control functions such as fault monitoring and protection. Now it appears that everything is working, again, mostly something got reset, so it is good news, relatively speaking.
The P5 is a rare truly powerful beast, and you obviously realize how tough it is to send 130 lbs bare/140 lbs in the box out for repair and have it returned/re-installed, so you really should start thinking about protection against lightning induced surges/spikes.