Under considerations for exposure control the workers would be being rotated in and then removed when their dose limit has been reached. Then they are no longer available to be exposed. Other workers would have to be found (and trained and briefed and sent up to the job). You can only send them back in if they can recover. Recovery from exertion or heat is pretty quick. Recovery from radiation exposure.... longer time if trying to maintain worker health and stay within regulatory guidelines.

If there are tasks that must be performed by specifically skilled people who aren't available or have already reached their exposure limit then the existing people who can do those tasks may wind up with radiation poising or dead because the guidelines no longer apply (This is war against catastrophe). Realistically this is probably the case. I'm sure there are heroic stories from this disaster that we don't know yet.