Fireworks, back and forth

From NBC's Domenico Montanaro
Romney has gone after Giuliani on illegal immigration and this question opened up the back and forth.  Romney went after Giuliani saying he did run a sanctuary city and cited his undocumented workers being welcome in New York quote from the 1990s.

Giuliani said Romney's house was a "sanctuary mansion," that he employed illegal immigrants. Romney took umbrage and shot back.

It was definitely the most fiery we've seen the candidates at a debate.

Also, is this a replay of the Democratic debate... where the two front runners dominated going after each other and then were booed off to move on?