Tell ashley to wait at the top of the stairs...after you enter the cell and he is free, run like hell! Just kidding..shoot a bell, when he goes to check out the noise shoot that cancerous looking lump on his back, he will croak after a few times of doing this. Flash grenades are no good because he is blind.
I've played resident evil 1,2,3, and am almost finished with 4. Nothing is cooler than turning off the lights and getting submerged in these games!