I was used to needing the flamethrower to deal with the shields, and that worked fine. Mika, however? Is immune to it, and it seems like he's also immune to explosives, as my regular frags don't seem to do anything.

The only way I can damage him is when his shield goes down while he's reloading, but then my sniper's accuracy flies out of the window and I can only get one or two shots in because they start wildly deviating outwards (something that hasn't happened before.)

Trying to get in close is extremely unpleasant due to his flashbang nonsense, so I don't think the Rotoblade will help. How do you kill this guy?