At the end of the film Phone Booth is Colin Farell actually dreaming or is that the real sniper?

Aslo if its the real sniper then how does the Pizza guy die? Cops shoot him? is the real sniper with the Pizza guy while he calls Stu? does the Sniper kill the Pizza guy? how does the real sniper get away? or was it all just Colin Farell just dreaming when in the Ambulance?