I can't finish the quest with the bonus because everytime I go anywhere near Dragon Bridge, Gaius Mora and his companion immediately run over to me with their swords drawn and attack me, there's no way to kill them in the city, and certainly no way to do it steathily. The guards do nothing but run away and the only conceivable way I can think of getting the quest WITH a bonus, is by leading the 2 (whilst they're swinging swords at me) to Solitude, the nearest city, and kill them after I lead them inside the gate. I'd rather not have to do that though.