Turns out SMG does a pretty quick work of him in his second form. Just aim for the eyeball and bait his combo attacks by staying relatively close to him, at the end of each combo he'll slam his arm to the ground and give you some time to unload a magazine in its weak spot. It works best on the hallway, so it's best to do this until you run out of space, then it's just a matter of finishing him off on the platform.
![](https://i.ytimg.com/vi/ctKt5jEKYZs/maxresdefault.jpg)