What about it?
If you're an admin user, @PID will use an undocumented API to return a pseudo-PID (not the real one, but one that Windows will associate with the process).
However, it's useless, because you cannot actually do anything with the PID. Even if you had the real one, Windows will still not let you do anything with that PID unless you're running in an elevated process. (In which case, TCC would have used CreateProcess(), and this whole exercise would have been pointless.)
So unless you just like to look at PIDs and imagine what you would do with them if you could actually do anything with them (and you can't), you can just substitute @RANDOM.