This song is lyrically very similar to 'Killers', describing the perspective of a hit-man as he prepares for the assassination. The feeling of the song matches perfectly what a real hit-man once said to a psychologist:
"I have a special power. It takes a special power to kill a fellow man and it gives you a secret something a force, a confidence, afterwards. [...] There is a something which I feel as I do the job. It is a private thing, but you know when you fly, at take-off, you feel a strange feeling in your body, not explicable, but strange. A sort of revolution in your belly. That's the way I feel when I kill. It's no mystery."
The music successfully manages to create a mysterious James Bond-ish type of mood, but unfortunately never rises to any type of climax. It is still a very good song, though.
Here we are trying to get into the head of a hired killer. He doesn't do it for money, but because he likes it and he's cool, calculating, cold and sadistic. These are Steve's lyrics again.
Bruce Dickinson