Corrected entry: In the pool scene, after Moriarty leaves, Sherlock sets the gun on the floor to help John out of his coat. After he gets it off and tosses it away, he goes off screen for a few seconds. He did not pick up the gun before he left, but he comes back holding it. (01:26:45)
Noman
27th Aug 2011
Sherlock (2010)
You can see the very beginning of a bending-down motion. This could be just because Sherlock is going to duck around the corner, but he could also bend down further to pick up the gun. Judging from the previous scenes, it would be lying left from his feet, just in reach. That we don't actually see the picking up doesn't mean it didn't happen, as it would easily fit in between the scenes.
Correction: When Sherlock goes off screen, he goes to pick up the gun and search the area for Moriarty and the snipers. It is obvious that Sherlock picks up the gun because he is seen bending down just before going off-screen.