Yo, longtime lurker coming out of the shadows... (this chapter is just too
I also agree:
1. Jung saw someone in the alley (hence the shocked expression).
2. He has no romantic feelings for Sul (yet) and has an ulterior motive to ask Sul to go out with him so suddenly. Maybe to decide on her reaction to see if she is already going out with In Ho? (which is why he gives up so fast after her initial rejection)Or perhaps it's to let that lurker know of their relationship.
3. After leaving Sul behind he goes to "take care" of that person in the alley
About the mystery person hiding in the alley:
* Both Jung and Sul know him/her
* Jung doesn't want Sul to see/speak to that person
* He/she has been waiting for Sul, or dirty alleys are his/her natural habitat.
Last year I think there were only 3 persons Jung could have manipulated into attacking Sul. The stalker is having a drink with the annoying senpai, the other is a girl whom I doubt likes to lurk in dirty alleys, and the last one is the homeless woman Jung gave money to and who attacked Sul in the library. I put my money on the homeless woman.