Dante's Inferno Guide

First walk into the portal in front of you, turn on the switch above, then return through the portal just now, and climb along the wall to the top to get the 12th silver coin. Return to the human wall, flip the switch and immediately return to the upper level through the portal, and jump to the opposite side through the extended time-limited platform. Wait at the portal on the right, and when the moving platform in the air stops in the upper left corner of the screen, enter the portal, just in time to fall onto it. If you find an opportunity to jump to the red soul water tank on the right, you can get the 13th silver coin.

Then when the moving platform stays in the upper left corner again, jump into the door on the side and move with the platform to leave the scene