In fact, when the incident occurred, he was not even in the room! So how is it physically possible that Sherlock Holmes was responsible for his death? He was not, in any way, shape, or form. Additionally, how could Sherlock Holmes know that the snake was going to go after Dr. Roylott? He did not set up anything to direct the snake towards Roylott. In fact, after the murder of Dr. Roylott, both Sherlock Holmes and Dr. Watson were in shock and a bit fearful of the snake. To keep the speckled band from hurting anyone else, Sherlock Holmes grabbed the snake using an object to grab its neck and trapped it inside Dr. Roylotts metal safe. Therefore, he was trying to protect the characters from the speckled band from potentially further and deadly