Quote MikeLikesSoaps: maybe the interruptions are on purpose to keep them from kissing so it will be easier for Brad to get involved with Lucas.
I think this is the more likely scenario. There have been many times we've watched two heterosexual characters get interrupted to build up suspense or anticipation, I see no difference here. I think they are making a point for Felix and Brad to just not be able to get together to open the door for Lucas to step in. I think a triangle is on the way for these three.