It's going to happen again. Check out the link to the thread in this post where those of us on the leaked 2.1 have been fighting this thing. Take Caddy's advice and get a replacement.
To summarize, we have tried several scenarios to try and replicate the problem but it seems to be completely random. I even went so far as to do a factory reset and run the phone that way with no apps at all for almost a week on factory settings and I still got the "silent phone" issue repeatedly.
Now it is up to you, but others pain is your gain. Save yourself the aggravation.
Best Of luck to you!!