Continuity mistake: When Van Helsing hypnotizes Mina, the candle he is holding changes throughout the scene: In the shots facing Van Helsing, long pieces of wax are sticking up from the top of the candle, while in the shots facing Mina, they're gone. (01:43:40)
Character mistake: At the beginning of the scene where the vampire hunters leave London in pursuit of Dracula, Jonathan narrates, "By train we can reach the Romanian port in Varna in three days." However, Varna is a Bulgarian seaport. This can even be seen on the map showing the Turkish invasion of Eastern Europe in the movie's prologue, and on the map that Jonathan studies aboard the train at the beginning of the film. (01:45:35)
Continuity mistake: When Jonathan is comforting Mina on the train, after Mina says, "Oh, what have I done to you", her head, resting against the couch, keeps moving up/down between different camera angles. (01:45:45)
Continuity mistake: After Van Helsing inspects Mina's teeth aboard the train, as Jonathan sits down next to her, his forehead is shining with sweat. After Mina says, "Oh, what have I done to you", his forehead is showing no signs of sweat. (01:46:35)
Continuity mistake: When Mina and Van Helsing are making camp in front of Dracula's castle, in the first shot, there is a bird's eye view of Van Helsing walking over to Mina with a bowl of food. In the next shot, he comes over with the food again. (01:49:13)
Continuity mistake: During the chase at the Borgo Pass, there are several shots of Dracula inside the wooden box, buried up to the neck in the earth of his homeland. However, when Dracula bursts out of the box outside the castle, the box falls apart completely, but hardly any earth falls out. (01:53:10 - 01:56:50)
Continuity mistake: In the last scene, when Mina Harker lays Dracula's body in the cathedral's altar, she kisses the vampire's lips and he turns into his human self. His face is covered with blood down from his nose, but after the kiss Mina's lips have no sign of blood. (01:58:45)
Answer: It's unlikely they were falling in love with Harker: they are sadistic, baby-eating monsters who regarded Harker as food and a temporary plaything. As for them sleeping in the open, the local populace dreads and avoids Dracula's castle, so there's hardly any fear of intruders. Van Helsing did enter and kill them, but they reckoned, mistakenly, that he too would be too afraid to do so, especially after their horse-mauling escapades the previous night.
Jukka Nurmi