I had trouble with this one too, i don't remember which program i used to extract it.
But if you only want the sound files.

This should work

http://darkmaster.quakedev.com/files/bo/bpill_0.8b.zip

Just to make sure we have the same file.

item number 2340(including empty files whithin PILL.BIG)
file size for 'item number 2340' = 48884 bytes
MD5 for 'item number 2340' = 420ecbee48681cf5bdc7c2dfce372a40

What does it sound like?

if you change sample rate to 16000
with
play -r 16k pill_2340.wav
or
sox -r 16000 pill_2340.wav test.wav

it should be fine?

I think it's item number 2340(pill_2340) not counting empty files in PILL.BIG.
I haven't played the game for a long time so i could be incorrect.
It is a WAV file so you can play it directly.