How is the water reaching the pan? It should be directed to the drain. If the drain is shot, then you are looking at a crummy situation involving on-going leakage.
Since you will be re-doing the shower, can you grout all cracks, grout the floor itself, and apply sealant to all seams -- including the seam around the drain? This might serve as a temporary fix until you pop for the full remodel.
Not a pretty solution . . . but it is temporary, right?