Has the writing style, pace, tense, or tone changed in Chapter 8?

Chapter 8 is different than the others for a few reasons. Despite its Gothic nature, Jekyll and Hyde is more or less a detective story. By this point in the novel Utterson should be close to solving the mystery. On the contrary, Utterson still has no clue as to the many questions surrounding the case. Here the tone of the story becomes rather desperate. Stevenson begins to move the pace of the plot faster. Circumstances come together that enable Utterson to stumble right into the thick of the mystery. Stevenson seems to give Utterson everything he needs, like Jekyll's scared staff for example. The plot seems to charge forward with Utterson trying to hold it back. He resists breaking down the door to Jekyll's lab; it just wouldn't be the proper Victorian thing to do. Finally Stevenson seems to almost force a conclusion with the final letter that they read which explains everything.