The account is locked down at the time of death and the bank should then cut 7 checks and deliver them to the appropriate POD beneficiaries within a reasonable period of time (i.e., after a death certificate is in hand).
The personal representative would have no access to the account because it's not ever a part of the estate. And of course, the two authorized signers lost their access at the time of death, also.
Be aware of any state laws that might affect your actions. One state I'm aware of includes a requirement that all beneficiaries be paid at the same time.