"Don't worry, dear. Suicide is not in his repertoire. He's far too fond of himself for that." - Dr. Watson
Ah, the lovely couple. I read some of the books before watching Sherlock Holmes, it was all quite funny. They have speedy back and fourths and these two (Holmes and Watson) can sometimes be very dumb about certain things that Irene Adler clues them in on. I recommend you watching it, but you'll probably have to re-watch it a few times to fully understand the theory.