Although Su Chen was able to communicate with the two fetuses, he did not want them to continue intervening. What if something went wrong?
Even though he had seen with his own eyes that the two embryos were indeed capable of suppressing the God-Killing Cauldron, no one could guarantee that further intervention wouldn't lead to an accident. If anything were to happen to the two children, he would never be able to forgive himself.
That was precisely why, after much deliberation, Su Chen ultimately chose to let it go.
Chapter 1654