I just stumbled across this sublime technique of concatenating DOS commands with &&, in order to run them on the same line.
EXAMPLE -- Does all of this in ONE execution of RunWait()..
set current drive to C:
change path to WINNT folder
collect the list of files there into a temporary file
open the file in your text editor
RunWait( @COMSPEC & " /c C:&&cd \winnt&&dir>D:\temp\multi.txt&&D:\temp\multi.txt", "", @SW_SHOW )