I hadn't got the chevo for getting through a gather with no damage to me or the little sister but noticed a good spot to attempt to get it in Minerva's den (also I found a technique which worked really well for me - Bees - Keeping throwing out swarms of bees and it distracts all the Splicers).  
  I did the gather twice without getting hit and on neither time did it give me my due - can you get normal Bioshock2 achievements in Minerva's Den or have other people had this problem?  
 p.s. I have also discovered that my invisibility gene tonic has stopped working - anyone had this either?

I got the no damage achievement in the main Bioshock 2 game. There's a gather point in a frozen room that's full of turrets. If you hack all the turrets and throw out a mini-turret of your own, it's pretty easy. The splicers can barely get to you. Bees would come in handy there too. 
 
So far invisibility gene tonic is working fine. Haven't quite finished it yet.