The point of walking on water wasn't the miracle of the thing, but this, I think...you can't just stay in the boat.
And you aren't supposed to dive into the water and sink.

To stay in the boat would mean to risk as little as possible, though in attempting to save yourself, you risk losing everything. And staying in the boat means focusing only on yourself and your problems. The chaos around you.

To get out of the boat doesn't just mean sinking to the bottom...that would mean life was meaningless. What would the point of risk be, if it only meant death?

To get out of the boat, then, is to leave behind what you think of as safety (which it really isn't), to let go of the only existence you can imagine capable of saving you (which it can't).

 It means existing between two places, safety and death. To walk on water means embracing what you thought was certain peril. And to find out that peril isn't what you thought it was.

Did Peter ever realize this?