Plummet means to fall, it's not something you can do TO someone else. For instance, you can't say. I fall you down the stairs, I fall you down the well. You should use a verb such as 'push' 'threw/throw', and so on.

You might like "hurled" instead of "plummeted". Robert's right, "plummet" is not something you can do to someone else. "You hurled him into the well which he dug for me."

I think it should be like this: You plummeted him into the well which is dug for me.

Word order errors