Takeaway. Nothing leaps through the fluid: current flows continuously along the inside of the axon, and myelin insulates each internode so the current reaches the next node before it fades below threshold. What is discrete is where the action potential is regenerated: only at the nodes of Ranvier. That makes conduction faster and cheaper, because far fewer Na⁺ ions have to be pumped back out.
Not to scale: real nodes are ~1 µm wide and internodes hundreds of µm long. Keys: space = play/pause, → = next step, R = restart.