To quote Anderw Bennett: "The 402 bold time is one of the most difficult routes to execute that does not use random elements, largely because of the continuous use of the [1/2] wait and quickly changing situations. A simpler 390 solution with the same principles is also shown below. Since there is no other dependable way to complete Block Buster consistently (as opposed to BlockSlide, for instance), aim for either the 390 or 402."
No other dependable way? I took that as a challenge and started looking. I found another approach that was slightly quicker for the first room that left 4 blocks on the sliplist, but that resulted in having to wait later on and generally raised the difficulty. This route has very little slide delay during the 2nd room (and what little there is makes the timing easier!) and ZERO waits during the 3rd room. The final room has a multitude of different approaches, this is just the one I prefer. A safer approach would be to loop around each ice slide between pushes, and if the top block gets pushed down to just ram the second block against it as seen here.