Although Cain had lost most of his power by this point, he was still strong enough to forcefully break into the secret dimension, so he just flashed forward, shattering the ground to pieces, and appeared in front of the massive metallic gate.
"¡BOOM!"
Cain could use the system to try and hack the gate's formation, but he did not have time for that, so he just clenched his fists and punched forward, battering the gate open and flashing to the other extreme of the clandestine prison.
The first time Cain appeared in this place, his mind immediately went to the people in those cages. He now had the power to break them open, but that would endanger his life, so the calculation did not even compute in his mind.
"¡BOOM!"