This is very hard to understand what your problem is
send me the ged and ill take a look at it if you like
just at a random guess, would putting a cap/limit on the max speed of the object that keeps pushing through the arena walls help?
Edit
or if you mean when it hits the wall it just stops moving completely then try using the same settings I have used on my example for your physical response in your game.
Edit2
your game is a little to big for me to download tonight, I have very slow internet
send me the ged or an exe with just one resolution so I can download it