You can store 'ls' in new variable like..

const ts = ls;

Hi, I'd recommend you first identify which test is failing, then comment out the other tests and add puts statements at different points to help you to understand what is happening in that test scenario. Hopefully, you should then be able to see what the issue is.

The error is very likely coming from: maze[verticalPos][horizontalPos]: you're attempting to access maze[x][3], where x is out of bounds.

A problem with your code is not a kata issue. Hopefully this may help: Troubleshooting Your Solution.