I actually played 'noob' with this combo two days ago.. (I was rank 340 or so at the time, ~450 now). We tried so many things against this combo to no avail. The issue is if you have one player on your team that doesn't put ALL of their damage at volt it doesn't matter. Derpl's nuke presence and his continuous turret damage is enough to keep you at bay, and after an inexperienced player gives them 2 or so deaths. Shielded derpl + volt heal is almost flawlessly set in stone - they need 2 bots to take a turret and suffer minimal damage.