Perhaps the next time you are in this situation you could say to the person you are talking to "Please excuse me a moment, I'm going through security. Could you hold for a minute?"

And you could say to the TSO "I'm sorry if I'm being rude, but this is a very important call."

Then you will have been polite to all parties concerned and most likely allowed to move on in a courteous manner.

Too many people forget their manners these days, especially when travelling.