A party that storms TV studios, seizes government offices and maroons thousands of innocent foreigners potentially getting power doesn't sound good. But that's if that were the only thing to worry about...
Now, not only are there a lot of angry now ex-government officials, there's fights between the two main rivals. I'm not surprised that Thai Security Officials are worried about fighting.
If the situation deteriorates much more, I wouldn't be surprised if a civil war breaks out.