Well, I think that if you have to suppress everything, that makes for interesting tactical decisions and means suppression won't always be appropriate. It makes sense that if you need to suppress here, and a buddy for some reason needs to cross your line of fire at the end of the corridor, there's a good chance you're going to put a bullet in him, right? Would an infantryman consider that firing at the ground, in a tunnel, 10 metres to the front, makes it safe and acceptable to cross that line of fire at 20 metres? I would hazard a "hell no".
Maybe fire beyond the target point gets the -1?? To allow tactics of desperation? So you COULD arc up the floor, but it doesn't guarantee that the area beyond is "safe".
Not being any kind of soldier, I always thought of "fire" as burst fire, "auto fire" as two quick bursts, "cover" as finger on the trigger waiting for a target, and "suppression" as NOT waiting for a target but going to some degree of "Hollywood auto fire" in order to render the forward region uninhabitable (hence no Leadership dodging: you don't get to dash across extra fast and not get shot at because at any given moment there are already bullets/beams/particles flying through the area).
Now, don't get me wrong, by "Hollywood auto" I don't mean running out into the corridor , standing feet beyond shoulder-width apart, gun held at groin level bellowing "GRUAAAAAAAAARGH!" while smoking hot brass piles up to your ankles and the band plays "America! **** YEAH!"...