If binance discover that you are running more than one account, as this is a violation of the conditions of use, it may lead to Account Freezes, Permanent Bans, and the loss of access to deposits with these accounts.
As for what will happen in the case of Merge, the activity of one of the accounts (which has not completed KYC) will be deactivated and allow the use of the other account, so then withdraw any deposits before taking the step.