Remote shutdown vulnerability ?

[Mike Zeinz]

Hello,
          I'm writing to this ML to report a dirty scene that happened 
to me.
          I have ubuntu edgy installed in a machine located at room A.
          Now, someone calls me to go to room B and locked me in that room
          that have a machine running Windows. I really don't remember 
if I've
          locked my machine in room A somehow with xlock or locked my 
terminal..
          For security reasons I decided to download putty and access my 
machine
          in room A and shutdown with `sudo shutdown now`.
          The thing was when I came back to my machine it wasn't off, 
and worst
          it had root at bob# terminal opened.

          What went wrong?
            Did I shut down the machine incorrectly?
            Is this a flaw? (...)
            What else can originate this flaw?
            How can I solve the problem?

Regards,
                Mike.