Film idea update

After talking to my group we have got a better idea of what are opening is going to be about. it's going to start with the character being chased (actor still unknown) who is on the roof of a building who's been sent to infiltrate the building for an reason unknown as we haven't figured that out yet. However two men enter the building in order to catch the infiltrator who now has to escape the building without being caught.
Now this is our first idea so there is a good chance that certain parts may be changed either to make filming easier or something happens such as not being able to film on the roof. We have also brain stormed some ideas which may or may not happen, First off the person being chased may have a ear piece with someone talking to them on the other side trying to guide them out the building, this next idea will most likely wont happen which is having the chase continue or the entire school grounds as when the man goes to escape the nearest exit is blocked off so he is chased around the building next to it. I say this will most likely not happen as we would firstly need to explain why the setting is in a school, we then would have to make sure there are few people around so that we can film without interruptions and we may need to get permission run around the whole site so in the end it's a lot of work just to get some extra footage. However one thing I haven't discussed with my group but may want to try to implement is having a stealth section in the opening were the person being chased has to sneak pass the men chasing him I think this would be a good idea as it will help make suspense and tension in my movie.