High are the hopes of many here for conventional romance to occur between the two main characters, and perhaps that may yet come about as a result of this anime-original ending I keep hearing about, but in so far as I've read in the manga (still the standard) that is, at this point, unlikely.
The cigarette-lighting moment didn't impact me so deeply, even if I am a hepless romantic, because Black Lagoon did not build up my expectations for that sort of development. It'd be quiet a challenge in fact for the author to turn away from his present train of style and cram in some conventional romance... difficult, but not impossible. Cameraderie would be the word at the moment, IMO.
The latest manga arc, Maid to Kill, seems to continue the author's preference for the gritty rather than the sentimental, as it is set off by this event:
Comes as close to the killing of a "good character" the storyline has seen so far. I still haven't had a chance to read the manga, but am tremendously happy about this inclusion of Garcia, Roberta and Co. as part of the reoccurring character lineup.