What is the argument for leaving them behind and in front of witnesses? Other than wanting them to be found.
To reload his handgun as fast as possible. A totally cool customer might take a few extra seconds to pocket the shells as he empties the gun of them, and remember to ditch them later (very important). But a flustered murderer might do as he did, dump the shells out as soon as possible to allow reloading the gun as soon as possible.
Sure. Wouldn't he assume the police would also be looking for a guy with a handgun?
Police are always looking for a guy with a handgun. But murders don’t always ditch a murder weapon. They may need it again.
"Immediately" as in 30 minutes later?
Immediately as within a few seconds of a patrol car drawing level with Oswald’s position on the street in front of the theater.
Curious, if Oswald wanted to sneak into a theater just to catch a movie, not to avoid the police, wouldn’t he choose a time when a police car is not approaching? I would think so.