Seward's Diary. October 3. Van Helsing and Seward rush in to find Renfield on the verge of death, his back broken and face smashed in. Renfield, between gasps, tells the two that Dracula appeared outside his window and promised Renfield an "infinite" amount of red blood in the form of rats, bats, flies, moths, and other forms of life—Renfield was so excited by this prospect that he bowed down to worship Dracula forever, and in doing so, invited Dracula into the house. Dracula then came into the window that night, as a mist, and proceeded to form into human shape long enough to beat Renfield to the verge of death.
Finally the relationship of Renfield to Dracula is explained in more detail. Dracula appeared to manipulate the nature of Renfield's illness, knowing that Renfield desired more kinds of life on which to feed—and in doing this, Dracula got himself invited into the building in which the group was planning to destroy him. Although Van Helsing repeats that Dracula is not a very clever monster, he nevertheless, here, deploys a clever strategy to enter the asylum.
Before dying, Renfield also tells the two that he fears Dracula wants to harm Mina, as Renfield believed he felt Dracula asking for Mina the previous night. The Professor and Seward are, naturally, quite worried, and decide to break into Mina's room to see what has happened to her and to Jonathan.
Dracula always seems to target women first, perhaps because there is a sexual element to his "blood link," or because he feels that it is easier to catch women unawares than to catch men.
They do just this, and find a terrible scene in the bedroom. Mina has been bitten on the neck by Dracula—her blood is smeared all over his face, and he is holding her head to a wound in his (Dracula's) own chest, forcing Mina to lap up the blood, Dracula's own blood, pouring out of the wound. Van Helsing and Seward are horrified by the scene, and Harker sleeps next to Mina and Dracula, unaware of what is going on, as though in a deep stupor.
Van Helsing pushes some of the holy host at Dracula, who is aghast at the sight and escapes through the window, where the group cannot pursue him. Morris and Arthur hear screaming (they appear to be residing in the asylum as well, while Dracula is being hunted) and say that someone has burnt one of the copies of all the documents related to Dracula—Van Helsing announces to Arthur that this was Dracula himself, and tells them what has happened to Mina, who has awakened in a groggy state, along with Harker.
It is important to note that, during Dracula's attack on Mina, Harker was lying nearly unawares, powerless to do anything to stop it. This seems as important to Dracula as the actual attack—the idea that the men surrounding him, the men attempting to thwart him, are not powerful enough to protect the women in their lives. Dracula hopes that Harker will feel that Dracula, now, is Mina's true consort. This, perhaps, answers the question of why Dracula attacks women—because his assault on women is also an assault on the men who love them (of course, the Victorian sexism inherent in such a belief, that the men would be unmanned by having their women sexually assaulted, is a different story).
Harker, while waking up, realizes what has happened and demands an explanation of what took place from Seward and Van Helsing, who attempt to calm him down. Mina, realizing that she has drunk Dracula's blood, fears that she has been "contaminated," and that she is now unclean, and unfit even to kiss her husband. Seward and Van Helsing and Harker promise that this isn't so, and say they are determined to help her and to protect her.
Mina recognizes at once that her blood link with Dracula will probably have terrible consequences. Not only has Dracula drunk her blood, meaning that Mina is on the path to becoming a vampire, but Mina has drunk Dracula's. Since no character in the novel has yet done this, the consequences of this terrible act cannot yet be known.
Van Helsing then asks Mina to recount exactly what she experienced—in a dream, she felt a white mist enveloping her, and saw, on waking in the dream, that Dracula was bending to suck her blood—she was powerless to stop him, and then Dracula forced her to drink his own, in some kind of reciprocal ritual designed to unite them spiritually. Mina curses herself for not doing more to prevent Dracula from securing this "transfer" of blood, but the rest of the men in the group say that it is not Mina's fault, and that, the next morning, they must set out neutralizing the wooden boxes, in order to begin fighting Dracula.
Again, the components of Dracula's seduction are in place. The mist represents the terrible viral quality of Dracula—that he can be anywhere at once, and that he can infect those near him. And Mina's response, that she should have done more to protect herself from this assault, sadly mirrors the response of many women after a sexual assault—that somehow they have invited the attack, and that they blame themselves for the violence done to them.