What do you do to get water out from under liner of a vinyl lined pool?

I just had this happen. I have an in-ground vinyl pool. About 10,000 gallons of water was under my liner this weekend. I took off the trim ring around the (normally summerged) pool light and slipped a small submursable pump with hose attached under the liner at the deep end. Plugged in the pump and let it run for a day - got almost all of it out.

I used a Rule brand pool cover pump, but any small submersible pump will work.