The excerpt expresses how Mr. Hyde could commit a crime that Dr. Jekyll would or even could not know about, therefore, could not incriminate himself even though they share the same body. This is made even more clear when the text calls Henry Jekyll "a man who could afford to laugh at suspicion", because he would not be the one who had done something wrong. It would have been someone else entirely. Mr. Hyde says it himself: "Think of it—I did not even exist!"
The answer is: D. Hyde is capable of vanishing to escape suspicion.