LordAardvark
Jack and a Krogan.
Episode 4 begins with Jack putting down the last name on her list she had at the end of Episode 2, before turning around and coming face-to-face with a Krogan merc who was hired to take her out. They recognize each other as former partners and reminisce about the time they crashed a space station together, before pulling the "ah, good times, good times. aight well I gotta kill you now. job's a job, you know how it is" thing.
Jack offers one last quick fuck, "for old times' sake." Lots of power dynamic switching between the two, with Jack and the Krogan alternating whose on top and whose in control of the situation. I want to pay special attention to the idea of extending the canonical Krogan quads and organ duplicity to Krogan cocks being double-barreled, I think a lot of fun imagery can fall out of that.
As Jack wears the Krogan down and gets her fill of him (and filling of him), she slaps some Omni-rings on his cocks and threatens to snap them clean off if he doesn't tell her who hired him to kill her. He swears he doesn't know who the client was, that he was contracted anonymously by a Turian. When prompted how he was supposed to report the job done, he gives the location for a dead drop on Omega.
Jack cheerily comments that he's just as much a pushover as he ever was, and that this was fun but that she has shit she has to do - "you know how it is." She promptly just leaves him there on the ground, Omni-rings painfully tight around his cocks. He awkwardly asks if she's really going to just leave him there, and gets no response.
Post-credit sequence will be the Krogan getting chewed out by the Director, before the latter realizes that Jack is going to be more of a problem than he thought - if he wants something done right, he's going to have to do it himself. His brooding is interrupted by a report that a ship is approaching the station. The Director turns his attention to the feed of Liara's shuttle approaching. The Director muses that Doctor T'Soni is precisely on time, and that he will need the perfect welcoming gift for her. As he flicks through various videos of Shepard getting gangbanged, he wonders aloud which one to choose.