I think the reason this worked for me was because I read about the urban legend beforehand. Because I knew the story it was easier for me to picture what was happening, plus the 'whys' to go with it.
I liked how you wrote Callahan. He came across as a very menacing character, his dialogue in particular had sinister undertones throughout. Good stuff.
I noticed a few times where you used numbers, '3' sticks in my mind particularly, but really you should write them out as a word, three, instead.
Also I felt like the final scene went on a little longer than it needed to. You could probably cut it down by a page at least, if not more. Some of the dialogue wasn't totally necessary IMO.
Overall a good job for a week.