In Episode I, Qui-Gonn, Kenobi and Amidala first encounter Darth Maul on Naboo in the hanger along with about 10-15 of Amidala's armed guard. It is at this point that Gui-Gonn turns to Amidala and says "We'll take it from here". Amidala and her armed escort depart a different way, and the 2 jedi take on Maul.
Later on in the saga, we learn that a lone person with jedi skills can actually be killed by armed soldiers, as long as there are enough soldiers. Many jedi are killed in the battle on Geonosis by battle droids in Ep. 2. Virtually all the remaining jedi are killed in Ep. 3 by clone troupers.
So, why didn't Amidala and her soldiers just open fire as a united front on Maul? Could he really have deflected all those shots?