Watch out chlove! These types of dialogue placement in the last panel are a pain in the comic's buttocks! And it needs to be very clear which character speak first without the word bubbles getting into each others' way too much. Rereading that last panel myself, I thought for a second that Roomie was speaking first and ideally you don't want that when someone reads your comic. You want everything to be as clear as possible (unless your comic's about, I dunno, confusion or something). 

It always feels like your trying to juggle with those word balloons when this happens as an artist, you try shoving them in to make them fit, and not overlap too much, or cross the "tail" of the word balloon with another... 

--> You can find these two strips in the old archive >here<!