Adverb referring to previous verbs

Question

つまり他人の未来を知る、という事は他人の現在と過去を熟知してなければならない訳だ。
それも、未来という答えを弾き出す為に、自分の人生と等価値になるほど深く。
だがそこまで他人の過去や現在を熟知してしまっては色々と不都合が生じてしまう。

I am not sure about what the second bold part refers to?
I believe it refers to the first bold one

Long story short, knowing strangers future you have to have knowledge of strangers past and present.
Moreover, in order to understand the future you have to have a deep understanding as much as you have for your life.
But, having such a deep understanding of others past and present will cause various incoveniences.

Is it correct?

Answer 1

Your interpretation is correct. But I'd say that there was an omission in the sentence and the reference is actually in the part that got omitted.
2nd sentence without omission would be:

それも、未来という答えを弾き出す為に、自分の人生と等価値になるほど深く他人の現在と過去を 熟知し てなければならない訳だ。

So, actually 「深く」 is modifying 「熟知し」(熟知する as end-form).
It makes sense though, to say that 「深く」 "refers to the first bold one" as you say...

Answer 2

Yes, it is correct. I think it may be a good question even for Japanese students.