Why would you be standing on top of a skyscraper?
Having been high up in many tall buidings myself, I personally would have a bit of difficulty detecting a pocketknife drawn by an antlike figure amongst other antlike figures in a dark alley so many stories below.
I think the cape alludes to a superhero, perhaps the character has super-vision, which opens the dialogue to many ideas, all a tad far-fetched.