It doesn't even work like this...

if(key_f)
{
snd_stop(tankidle);
ent_playloop (my,tankidle, 77,0);
}

if(key_g)
{
snd_stop(tankidle);
}

There's just no way to stop the sound... I thought the problem was measuring key presses, variables, and if/else branching... But this is a shocker. I can't even use two separate keys to start/stop the sound? Makes no sense to me. I've done things like this before, and never had the problem...