There is no way you are going to make that walk in 10 mins...not walking. Jogging yes, walking no. It takes at least 15 mins.
Is it faster than taking the boat? Usually, yes. I have left the BW boat dock, just as the boat is leaving...I have walked to Luna Park, cut through and then on to DHS. I got to DHS, bag check, just as the boat was coming around the bend. We beat the boat by about 5 mins..but my friend and I are peppy walkers, we don't stroll.
If it were me, I would take the bus to BW from DTD, check it out, and then walk to DHS from there. It's an easy walk, along a very well lit and laid out sidewalk, that runs beside the canal. If you just miss the boat to DHS, I would definately walk, rather than wait for the next boat.