- あのさ、もし意識思考そのものが自律して この体を逃れたなら (Sung by Mary)
- 意識は自律して? 興味深いわね (Sung by Renko)
わね indicates that the speaker is a woman.
わ indicates that the speaker is female.
ね is used for the emphasis.
- 興味深い （It's interesting.）
- 興味深いね (It's interesting!, or It's interesting, isn't it?)
- 興味深いわ (It's interesting. And this is said by a woman.)
- 興味深いわね（It's really interesting. And this is said by a woman.)
You may know that the Japanese colloquial language has masculine wording and feminine wording. And わね is the latter.
Well, I explained a usual/normal explanation thus far. I mean "a usual interpretation without sarcasm."
However, sarcasm changes everything.
Whose interest does「興味深いわね」refer to?
The interpretation may be tricky. If it is sarcasm, it is translated as "Consciousness being independent? You’re really interested in that, huh."
If it is sarcasm, it is said by Renko, and it is Mary's interest.
If it is not sarcasm, it is said by Renko, and it is Renko's interest:
"Consciousness being independent? Cool! It's interesting (for me too)!."
I'd vote one for sarcastic interpretation because of the whole lyrics.
The わね has nothing to do with the determination whether it's sarcasm or not.
Only the whole context and the tone of the voice are the key to decide which.