[not_apathetic_anymore]

It's not clear from this article, but from others online there were at least 3 other agents with Bush. So he was not separated from all of his guards.

The incident is concerning, but there were apparently some USSS on the inside of the room, and Bush wasn't completely separated from protection.

[not_apathetic_anymore]

nevermind... I misread that article I linked to. But I'd bet there were some agents inside the room - and that they'd been there since before the president arrived.

I don't know that for a fact, but I'd lay some reasonable $$ on that.

[FairOpinion]

The "other three" does NOT refer to other 3 SS agents, but to the Chilean Pres, his wife & Laura. Bush was with them, then he left them to go back.

" Bush noticed the fracas after posing for pictures on a red carpet with the summit host, Chilean President Ricardo Lagos and his wife and first lady Laura Bush.

Abandoning the other three, Bush walked over to the agents, reached through the dispute and pulled his agent from the scrum."

[El Gato]

but from others online there were at least 3 other agents with Bush.

From your link:

Several Chilean and American agents got into a pushing and shoving match outside the cultural center where the dinner was held. Bush noticed the fracas after posing for pictures on a red carpet with the summit host, Chilean President Ricardo Lagos and his wife and first lady Laura Bush.

Abandoning the other three, Bush walked over to the agents, reached through the dispute and pulled his agent from the scrum.

The "other three" are not three agents, but rather "Chilean President Ricardo Lagos and his wife and first lady Laura Bush".