It doesn’t say WHY they did it or what they planned to do. They actually didn’t do anything to the phone system based on what I read, just that they pretended to.
That'd be something like the "office phone" that sets on an end table and is used, with permission, by guests.
They opened the handset, closed the handset, and called the phone twice.
Hmmm ~ deep crimes.
The wire room thing is irrelevant. You could go into any office and ask them where the wire room was and 99 times out of 100 the person you were addressing would say 'Hunh?"
It may have been their motive to show what doufouses the staffers are in Moon Landrieu's daughter's New Orleans office ~ although I don't know why you'd have to prove that ~ it's not like Senators keep that stuff secret.