Blast

(1) hire out your local family swimming baths for the day

(2) hire a bunch of pretend weapons, some balaclavas, and a bank of CCTV monitors

(3) get 30 random people off the street and divide them into 3 groups. Tell one group they'll be the terrorists, one group they'll be the swimmers/victims, and one group they'll be the cops.

(4) randomly walk among the groups and film them doing whatever they want for a couple of hours, then edit the footage down to about 90 mins

(5) find Rutger Hauer, put him in a small dark room and film him mumbling to himself for a while. Add that to the footage you got in step (4)

(6) get some generic 'important' sounding backing music with plenty of orchestral creschendos and marching drums, and play it non-stop over the whole thing.

et voila, your very own Blast. Enjoy!