For our Thriller opening scene, we have a group of ex-military soldiers who take a government building and its people inside hostage. My idea for the ex-military hostage takers in the scene is to wear a predominantly black outfit, with black trousers and shirts, topped out with them wearing black balaclavas. This is to add mystery to the characters because you will not be able to see their identity, and also because this stereotypical of what kidnappers would wear.
The other characters in the opening sequence are the hostages themselves. As these characters are in a office building, they will all be wearing suits and be smartly dressed. However, as they are hostages they will have black bags on their heads and will be kneeling on the floor.