After seeing the Watching documentary, ive learnt that an opening to a thriller should "seduce the audience into wanting more". From the examples played in the clips thrillers tend to open in one of two ways. One opening tends to be slow and creepy, which confuses audiences into wanting to carry on watching, and example of this would be The Shinning, Where a car is followed in a rural area. The camera was at a birds eye view, which almost felt like a helicopter was following the car. Which set an creepy curious atmosphere. Whereas, with the Step Father the story was beginning and the titles rolled in discreetly not disturbing the opening, then reaches a climax/unexpected event which shocks the audience to carry on watching.
Personally I prefer the second way, as its more engaging and doesn't distract the audience from the plot. Also i find that the sudden shock used in the Step Father, where we see the camera pan to the murdered family more effective. This opening and the opening to pelham 123 inspired our opening in our Prelim film.