I was mining at high rift activity quite deep (around 0.25). I figured it was safe because I just got there so my stability was high, I was right at the mine shaft, and the room I'd dug out was lit up. My stability had dropped some but it was still near the top and I wasn't getting the creepy sound effects you start getting. I turned around and was shocked to see a tainted drifter. I bolted for the ladder and went up but had half a dozen drifters popping out of nowhere around me. I am the most cowardly wimp ever, so have avoided mining if it's not calm since (especially that mine since it's near the tier 4 spawn boundary), but wanted to see if anyone had more information because this doesn't seem well documented. I've been mining when my stability is so low the screen starts jumping, but nothing spawns. I believe that has been calm and low rift activity times. If it's apocalyptic out do you get drifters appearing in fully lit areas if your stability drops just a little?