The God Slaughtering Formation was a forbidden formation technique used in ancient times to kill gods. As long as the person presiding over the formation core was strong enough, even a real god would not be able to escape it.
There were only two ways to escape the God Slaughtering Formation. One of them was destroy the formation core outside the array world, while the second was to use a strength that even the array world could not withstand.
Of course, it was impossible for the people trapped in the array world to destroy the formation core outside the array world, so without the help from others, the only way to escape the array world was to tear open an exit with a strength the God Slaughtering Formation could not withstand.