Mise en Scene in your Thriller sequence is extremely important. If your character(s), set, locations, lighting and props do not look 100% believable then the audience will not take the story seriously and will not be gripped.
You must aim to create a painstaking, stunningly accurate recreation of your fictional world – this quality (of appearing to be real) is called verisimilitude and is a key component of enabling an audience to ‘suspend disbelief’. This means they can forget that they are sitting in the middle of a hall full of strangers watching some light flicker on a screen and instead be engrossed in the fictional world that you have created.
If they are not convinced by the reality of your film then the audience will not have any emotional connection to your characters and will not care whether they are in great danger, have only a second to save mankind or [insert any other suspenseful scenario]. Instead they will be constantly aware that the characters, events and world are not genuine and will not give a monkey's who gets shot, savaged or squashed.
You are making the first two minutes of a feature film, not the first two minutes of a ‘student’ film. Make it look convincing through careful research and sourcing of all mise en scene components.
Costumes, Lighting, Actors, Make up, Props, Sets and/or Locations are all separate categories that need major consideration and a minimum of 2 blogs each – one about researching and another about sourcing the materials.
One little mistake on any of these details will blow any semblance of reality, the audience will lose belief and your thriller will be toast. For example: freaky tattooed psychopath defacing photos of former girlfriends in homage to the title sequence from Se7en. Beautifully shot and edited, unnerving original soundtrack, scary as hell, what a nutter.
Except he is scribbling out the faces of the girls with a berol felt tip pen. Budget.