There is probably an element of sentiment factor for Giffords in this which will not be there in Nov.
I’m going to guess that the “Giffords factor” WILL be there, very strongly, this November and beyond. Anybody connected to Giffords on that terrible day shouldn’t have any problems in winning that Congressional seat, for as long as they want it, unfortunately. It’s very similar to the “Kennedy factor” in Massachusetts (and, sometimes, in other states), where all members of the Kennedy family are connected to JFK and are treated like Gods, by way too many voters, for always.