From the New York Times:
On Saturday night, attending a dinner with leaders from the 21 countries that make up the Asia-Pacific Economic Cooperation summit that was meeting here, Mr. Bush had to wade into a group of security agents to pull his lead Secret Service agent out of a shoving match with the Chilean police.
. . .
Chilean security agents initially prevented Mr. Bush's lead agent from following him into a dinner for heads of state attending the conference. When Mr. Bush noticed the commotion, he walked back outside, reached into a group of scuffling guards, grabbed his lead agent by the suit and pulled him out of the melee. Mr. Bush then shook his head, as if in disbelief, and escorted the agent into the dinner.