Bitcoin's vulnerability to quantum computing is not a blanket threat, but concentrated in dormant addresses with exposed public keys. These include many of the oldest coins from the "Satoshi era" and lost wallets. These legacy holdings could become the primary targets of powerful quantum machines. These wallets offer attackers with time, scale and minimal resistance, making them the most likely starting point for future quantum-driven disruption. Dormant wallets combine three characteristics: no defensive action, long exposure windows, and high-value concentration. They also hold coins secured by older cryptographic methods. However, if the owner has lost access or is no longer active, these coins remain permanently exposed. The most exposed Bitcoin addresses include those with no additional layer of protection.