The private keys of your NGRAVE accounts in Rabby Wallet are on the ZERO and never leave the ZERO. That is a crucial difference with regular accounts in Rabby, for which the private key is stored in Rabby itself.
Each and every transaction from your ZERO account(s) will always need to be signed with your ZERO. It is simply not possible to transact without signing off with your ZERO first.
But this doesn't mean that nothing can happen. It is still possible to sign a malicious transaction and lose funds. For more information on how to avoid this, read How to stay safe on Web3.