3 weeks can be a long time, but remember that during those 3 weeks the ride will be testing regularly for staff training. Whilst something could still be done, it takes away time from training whilst it's installed, checked for safety, etc. And I believe that the ride has been running for training lately.
And in any case, here's an image from early 2019 (lifted from Google Maps of course):
Compare with the image EpicSmatty posted:
We can see the new theming has already been installed. Maybe there's more to add to it though.
As I say, at this stage I'm expecting that when the pool is filled with water, it will look like a boat that's there is sinking, and the rest could be for some sort of special effect, like some sort of water splash/fountain/explosion. But no idea really, so curious to see what it is.