This will cause mIRC to restart without taking into consideration the location of the mIRC.ini that was used during its original launch. It appears to be launched from C:\Users\You\AppData\Roaming\mIRC
Looking at this again, it probably would make sense for mIRC to use some of the original command line when "/exit -r" is used. If a scripter wants to have more control the /run command can always be used. Unless someone sees a major issue with this, I will make the next version use the -i -r -noreg and -portable switches from the original command line when "/exit -r" is used.
That would probably be fine, but just to throw in another option, you could also consider adding the ability to put those command line switches into /exit ... the only issue there is that -r is a command line switch and also an /exit switch.