The dock extension where Sentius Veros stands is built with furn_de_rope_03, a vanilla rope mesh which lacks collision. This means you can fall off the dock after exiting the boat, before completing chargen or unlocking the controls. Since you can't jump, pick up items, cast spells, or open your inventory at that point in chargen, there is effectively no way to get back onto the docks.

To fix this, someone just needs to add a couple more of the invisible CharGen walls to Seyda Neen.

I was tempted to mark this as bug as "critical," but it's obviously not a big deal in practice given that I am apparently the first person to notice this.