Oh, you want more details. Fine.
When he got to the park that he was going to bike he noticed a lone man in a dark suit carrying a side arm, but since it was just one guy he figured it was probably a sheriff or something and went on his first loop.
After the first loop he stopped to get some water and sat on a fence. The guy was still there, but now a couple of expensive mtn. bikes were also sitting around. As he sat there about ten black suburbans converged on the little parking lot. Out of each car came more men in dark suits with side arms. And behind them came our former President wearing mountain biking shorts and a western shirt with pearl snap buttons. He spotted Sergio on the fence and said hello.
"Hey," answered Sergio. Not hello, sir. Not hello, Mr. President. Just hey.
Sergio watched as Bush picked his bike and warmed up a bit. Not really knowing what else to do, he finally got off the fence and prepared for his second loop. As Mr. Bush rode back by he looked at Sergio and asked, "You want to ride with us, big guy?"
Sergio quickly took into account the many secret service agents with guns and his three days of mountain biking experience and replied, "That's okay, you go on ahead."
Fifteen minutes later he asked the secret service agents that were left behind if he could continue riding. He was told to go on, and he rode fast to see if he could get catch up. He never saw the riders again, but did manage to have his first fall.