I have no idea why someone would leave 5k in one of these accounts. That is ballsy and without a good password its mostly your fault. Good luck.
I would not leave it there for long. I was selling some coins and found out later that I could only send $1000/24hour back home. In any case, Mt.Gox has responded now to my ticket and as soon as they have a bit of time they will look into this. There might even be some resouces left. I'm starting to get a bit of hope.