Ask HN: What happens to BTC/ETH if secp256k1 has a backdoor

I have been learning about ECDH and that the difficulty of the discrete logarithmic problem depends on the particular curve. The NSA story around Dual_EC_DRBG did not help. Since its Abelian, if someone has hack x (P) = Q ... then the backdoor would be a 1/hack x (Q) = P.

Wikipedia: secp256k1 - " It's constants were selected in a predictable way, which significantly reduces the possibility that the curve's creator inserted any sort of backdoor into the curve."

So my question is what is the doomsday scenario? Wallets are set to hashes of Q (public key derived from P) so this should prevent anyone from having the Q of the ECDH to be able to back into the private key P? Is this accurate?