Since Patrick's been able to recognize that the door handle had something to do with getting outside (we love anything that's not indoors), he's been battling to get at that door knob.
It's his nemesis, his arch-enemy, his singular challenge in life. Once defeated, he can move on to the next one. But, until then, the battle rages on.
Thankfully, he has not realized there is a deadbolt we can lock ... now that he can actually reach the knob.