I agree with a couple of posters here.
I don't think being a tester alone will assure your foot inside the door. You do have to do something to stand out from the other 3-300 testers (large I know but you get the point) in the room. I can imagine learning the actual code and fixing your own bugs would go a long way in the eyes of the programming team, as would approaching the design team with meaningful, but small ideas.
That said, as MattP stated, much of the business world (remember gaming is still big business on a certain level) is about who you know and what connections you can make in a limited amount of time. Testing is a great foot in the door to meet people and create relationships that you wouldn't otherwise of had.
If I was a tester I would try to meet a new person of the team (have a nice long chat at lunch or on break) each and every day. I would talk about how they got started, what their working on and if the conversation is going well, how they would go about my search for my place in the game industry.
On the same note, conventions are amazing for meeting people and I would highly recommend that before investing 6 or more months of your life as a tester. I remember at the Austin Game Developers Conference a couple of years ago I met and talked with Richard Garriott for a small while. Now does he remember me now? no, but if I had been looking for a job at the time and had sent him my resume that night I would of had at least a better chance to getting an interview.
Then again I don't really know too much about the game industry as I'm not even in it yet, so take my advice with a grain of salt. =P