Math lesson here. As each HDI has independently 70% to restore after battle there are three possible outcomes. you have 49% (0,7*0,7) chance to save both HDIs 9% (0,3*0,3) chance to lose both and 42% to lose only one.(summing individual chances of losing only first and only second it's 0,7*0,3+0,3*0,7=0,21+0,21=0,42, or by eliminating other possibilities it's 100% - 49% - 9% =42%) Then in second battle assuming only one survived you have again, 70% to save it and 30% chance to lose it. By laws of probability the chance of losing one in first battle and then losing scond one in second is 0,42*0,3=12,6%. Not particulary high chance, but far from impossible. That's just a chance of this particular outcome though. Overall a chance of losing both HDIs in two battles is just over 26% (9% of losing both in first battle, 12,6% of losing one in each battle, 4,41% of losing both in second battle, separate outcomes so we sum it up). Again, far from impossible. You just had bad luck mate.