If any blocks in the RM lack reset inputs, your only option might be to stop the clock, either to the entire RM or to those specific blocks, until EOS is asserted. You might be able to surround these blocks with decouplers inside the RM, allowing you to force all inputs to non-triggering safe values until EOS is reached and prevent problematic signals from contaminating the rest of the RM. However, this might not stop a block without a reset from becoming internally corrupted with no recovery mechanism.
This block cannot be reset, but by decoupling its outputs, you can (perhaps temporarily) avoid corruption of the rest of the RM. Decouple its inputs to reduce the chance that other RM signals put it into a non-idle state. If it is not already corrupted from GWE, you are trying to avoid accidentally starting it.