<p>BAGHDAD, Aug. 22 -- As soon as he could pick himself up off the floor of his room and remove the shard of glass embedded in his right leg, Army 1st Sgt. William von Zehle rushed toward the sound of the explosion.</p>
<p>The 52-year-old retired fire chief from Wilton, Conn., surveyed the rubble and carnage. As he pondered what to do, a man in a blue U.N. baseball cap approached. "We have two people trapped! Sergio and Gil are trapped!" the man said.</p>
<p>The names meant nothing to von Zehle, he recalled today. But he went to look.</p>