it will execute with system account, no other permissions needed.
check the About specifying the file location and execute command for remediation.
under help files you need to specify the full path of msiexec and then the /q switch
If you do not select to download an installation package, you can still specify a command for the client to execute. The client tries to install the missing application. You specify the command by giving the full path name of the executable file. FTP and UNC paths are supported. If you are familiar with variable representation, you can modify the command entry. Also, if you need to allow another application to be used to execute the program that is downloaded, you can modify the command entry. The following is an example of proper syntax:
C:\program files\WinZIP\winzip.exe -a -s %1 -r c:\temp