You will not be able to get a different mission from the soldier who gives out that daily. meaning that at 2 a day you won't get to 15 for 8 days vs 5....Meaning instead of 40 days to get the Polemarch set, you are talking about 64 days. Also, if you haven't yet completed the other 2 missions that soldier gives, you cannot complete the full checklist of all the missions(each one gives 3 different missions randomly). My suggestion is to go far enough that she will stop following, then go back to the roof to get a new Soldier to follow you. That sometimes shakes it loose. Also I find that going past the barrel then doubling back to it from a steeper angle sometimes works. It's a crapshoot. BTW. if you are going to do 2 a day, when you are at 14/15, only do 1 mission before cashing in. Cashing in a 16th mission on the 8th day will NOT carry over to be 1/15 for the next set. Cash in to 15 with the commander and kill the bounty, then do the 2nd mission to register the 1 tick towards the next 15.