There's someone at both doors in this clip from the Dexter episode "Teenage Wasteland." They are coming after Lumen.
Added:
Dexter tries to bond with Jordan Chase on the episode "Teenage Wasteland." He's seen here chatting with the self-help guru, following a tough work out.
Added:
The pressure on Dexter builds this week, as Quinn gets a hold of the photos Liddy snapped of him and Lumen disposing of Chase's body. Get an early look at what that will lead to on "Teenage Wasteland."
Added:

Dexter Season 5 Episode 9 Quotes

Lumen: Share something with her - what you did when you were her age.
Dexter: I killed the neighbor's dog.
Lumen: Well, don't tell her that.

Dexter (thinking to himself): Jordan is one tough nut to crack.
Jordan (out loud): You're one tough nut to crack; you know that, Dexter?
Dexter (still thinking): I wish he'd stop doing that.