I lost mine in a very embarrassing way. It was in pre-searing. Now before you jump to conclusions, of course I didn't get killed by a scale or something. I didn't die at all from mobs. What happened was I was in the catacombs, and I got to those traps. I was a ranger with a pet, but I remembered from playing my necro that you need something to trigger them. So, I thought, maybe my pet can do that. I edged towards it, and stood on the very edge, hoping that my pet would walk in front. He did, and the explosion of it took me out, instant death. Survivor lost before I was even out of pre.

I didn't bother restarting, and I actually got enough XP without any further deaths to get the first level of survivor (just the 1 death), but I preferred the freedom of not caring. As soon as you die once you don't have to be afraid of it!
So where did you lose yours, if you remember?