if you look from under the car at the fire wall near the rack, and almost the center, but more to the pass side, you'll see a rubber tube with a elbow coming out the fire wall. thats the a/c drain.
the sound you hear is the heater core tho. if it was the pan holding water the floor would be soaking wet.
if the core is air bound, nothing will come out them two hoses when removed likely. if you like you can put a funnel to one hose, hold them both up in the air together then pour some coolant into the hose with the funnel till coolant comes out the other hose. then you lost no coolant, but only filled the core up.
you could hose flush it, then blow it out and refill with coolant too.
