When a hacking threat forces you to stop trading and withdrawals, the real gap is proof: you cannot say fast enough which keys are still safe.
The Crypto Times reports that GOPAX halted trading and withdrawals after a hacking threat and moved user crypto to cold wallets. Moving funds to cold storage is the right instinct. A halt is the blunt version of it: you freeze everything because you cannot name the parts that are already contained.
I review hot and cold wallet splits and where private keys actually live, so a threat turns into a scoped action instead of a full stop. If you run an exchange or custodial wallets, tell me how your funds are split today and I will tell you what a threat day would cost you.