It took almost an entire day for the dust to settle and the molten ground to cool down after the explosion, but there would still be a few more days before they could continue with phase four.
Not to mention everyone that needed to recuperate after suffering internal injuries from the aftermath of the explosion, the measurements and details of the plan needed to be revised with the data they had collected during the third phase.
Since phase four was the final stage of the plan, where the first three phases would be repeated all over the wasteland until not a single drop of rat blood is spilled, no matter how many explosions they set off, it requires proper planning. Unlike the first edition, where they just winged it while making sure not to let any rats live, every repeat will bring further results that will further enhance the plan.