Horror film Planning - Plot and title

The first thing we did as a group was to come up with a plot for our film, we came up with about 3 different plots but when we sat down and thought about them it became apparent that none of them would work. we then spent the rest of that lesson thinking of ideas to use, at the end of the lesson we still didn't have a plot.  During the weekend one of the members in our group had the idea of a sequence that leads up to a child getting run over, we discussed this and all agreed that it was a good idea so then started to expand on the idea. 

• The final plot ended up as a teacher driving home from the school that he works at and the lead up to a teenager getting run over because the teacher looses concentration because his phone rings, as the title sequence. 
• The opening sequence is the next shot from when the car hits the teenager, this includes the teacher getting out of the car, seeing the blood on the bonnet of the car and on the road, panicking, stumbling back into his car and speeding off, whilst he drives off you can see the teenager in the rear view mirror covered in blood.
• the plot would the go on to reveal that the teacher works at the same school as the teenager was from, the teacher then panics about it and becomes mentally disturbed and starts to kill other teens from the school until the police find out about his actions and come to the school the event ends in a hostage situation and the teacher gets shot the camera then pans around to see the ghosts of all the teens that he killed and him in front of them all.