You've got a lot of mixed things going on there, which breaks the physics behaviour. Don't use set position, don't use 8-direction, don't use anything that manually overrides the physics behaviour.
Instead, rework your project so that any object involved in the physics interactions is set to use physics forces, impulses and/or torque. Anything else that doesn't directly affect the positioning of physics objects (like the box front) should not have the physics behaviour.