In terms of neurons, the outside is more positive than the inside. Thus, a potassium ion trying to make an escape (due to it's concentration gradient) should be deflected/repelled back into the neuron. Those ions should be bounced back in when they reach close to the surface. But since not, this leads me to think that the outward acting "force" of concentration gradient is more powerful than the inward acting force of the electric gradient. So, why is the outward acting "force" of the concentration gradient more powerful than the counteracting inward force of the electric gradient?