What happens if a character’s velocity is greater than 0m when the character gets a Phase?

I’m preparing to run a Hero System, 6th Edition campaign, and I’m struggling to understand movement, especially velocity. Here’s the question: When a character’s Phase ends yet his velocity is still greater than 0m, does the character’s velocity affect what Actions the character can take on his next Phase?

For example, Slick’s Phase ends, but his velocity is still 20m. On Slick’s next Phase, can he take a Zero Phase Action to add velocity (E61 156), spend a Half Phase to take a Half Move during which he adds even more velocity, then spend a Half Phase to take an Action that requires an Attack roll, despite Slick still having a greater-than-0m velocity? Or, because Slick’s velocity is 20m at the start of the Phase, must Slick first take a Full Move or Half Move to reduce his velocity to 0m before the character can do anything else besides move?

Note: My confusion stems from this statement: A character "may not deactivate the Movement Power until he decelerates to 0m normally or through some outside means" (E61 156 and E62 25). So far as I can tell, the game doesn’t describe exactly what this means (i.e. I can’t tell if not moving is supposed to be the same thing as deactivating a Movement Power). Further, the game doesn’t seem to describe how already having velocity when a Phase begins impacts the character’s ability to take Actions. Finally, I’ve found no examples that cover what I imagine is this relatively common situation.