あの慌てようを見るに、危ない落ち方をしたのだろう。
The context is that the speaker fell over and hit his head, and his mom screamed and ran over.
I think that it means something like "Seeing her panic, I guess it was a dangerous kind of fall", but what on earth is the に? I can't find anything about に attached to a verb except for には, but even if the は can be omitted, the meaning doesn't seem to fit.
