To get the 10th ending press the red button until the roman pop up, do 213121 then flip the lever on the left. enter on the panel that just popped: 1066. the on the thing that looks like a lot of buttons do
at the last row you want to put the red on the 2nd square and the other at the 6th square.
at the first row you want to put one square on the very middle.
at the third row you want to put one red on the first square and another on the last square.
Done!
Credits: @tricky diamond and @dollarstoretankman