Well at least your's doesn't freeze completely!! lol.
Im having that problem your describing except instead of allowing the game to continue playing; it freezes and doesn't allow me to continue playing.
Though in honesty I believe it is partly due to the GPU overheating
(when it overheats I believe it freeze's up), and due to the fact that I lack the "Xbox 360 New / Elite Type GPU Heatsink /w Heatpipe
". In my scenario though, I had to re-apply the thermal compound to the heatsinks; though I have followed the instructions to the T, so I don't believe it is due to my lack of skill
So in the near future when i get the new Heatpipe, I will fill you in on whether or not it fixed my problem for me.
Otherwise fill me in on what you did to prevent this from happening!