Because of how much power he stood to lose and the risk of death, whatever motive he had for removing the Chaos Supreme Metac had to be extremely important. It must be so important that it was worth dying for. Anything less just wouldn't do.
The second price he was paying for this benefit was that the 4-D prototype couldn't accept any more normal 3-D prototypes. It would reject any incompatible Supreme Metac.
If he forced the 4-D prototype to use a normal three-dimensional Supreme Metac, then the fourth dimension in the subsequent cubes would stop growing. So, the only way to expand the 4-D prototype is to let the Chaos Supreme Metac absorb the incompatible ones.
He didn't mind these costs at all since he couldn't actually activate the other Supreme Metacs in the spark of power ever since he installed the 4-D prototype and gave it full rein. Even if he could use them, he would still pick the Chaos Supreme Metac and the 4-D prototype because they were vastly superior.
