[slg]

Right at the end of the section you quoted states he would have been able to leave in such a case. He would have been allowed to leave the airport if he was willing to "be escorted out of the secure area (and usually the terminal)." The problem is that Mukerjee wanted to leave the interrogation area and immediately reenter the security line. Don't you think it would have been a little pointless for the TSA (ok, more pointless than the TSA usually is) to allow people who were stopped in security to simply restart the process again in hopes they wouldn't be stopped a second time?

[wavesounds]

I was told by a TSA agent you have a right to go through the scanner again to check for false positives. So yes you are simply allowed to restart the process.