I suppose she could engineer a low probability scenario he couldn't react to, but I also can't imagine how she'd pull that off in a featureless environment. Grenades + her new Krakoan arm weapon maybe?
Afterthought's power is pretty compelling here, as he'd just see her attempting it anyway though. He'd even see himself tripping, if that was her plan, and re-adjust. I'd still lean towards him.
Then again, Midnighter's extra armor trick worked. Afterthought should have seen his hands breaking and didn't. Not sure what to make of that.