Everybody seems to think this is such a bad idea, but I did it myself when my lager didn't carbonate in the bottle. It does NOT oxidize the beer, at least not enough to ruin it in the short time it'll take to finish it.
What's there to lose anyway? Here I had a batch that was undrinkable, and I ended up putting it into my keg and having a few friends over. It was gone over the weekend, and everyone thought it was the best beer they ever had, myself included. I have a batch of stout right now in the same condition, but stout is a little tougher because you don't want it heavily carbonated and it's better with Nitro.