Thomas Was Alone

There are two pickups in 'Purge', pickups are small black squares.

1. Level 4.4 @0:04
After you pass through the 3rd checkpoint the pickup will be to the right under the second block with spikes on it to the right, its hard to see so if you miss it land on the spikes below to retry (As I do in the video)

2. Level 4.8 @0:46
Immediately upon starting the level press / to switch to Claire (Blue) and move left to place Claire next to the spike wall for John (Yellow) to jump on and jump to the pickup which is right next to the spike wall so you will die.

Here's a video

This is for anyone who got all the collectibles but did not receive this achievement and maybe another one.

After having beat the game and getting all collectibles I didn't have the 'Lone Survivor' or 'The Collection' achievements. My tracker read at 50% for Lone Survivor and 95% for The Collection.

I repeated both levels with collectibles for Lone Survivor but neither collectible was present because I had already grabbed them both.

The only way that I found to fix this was to delete your save of the game from both the cloud and your local save on your Xbox.

After doing so I played my way back up to 4.4 and the collectible was there. I grabbed it and both of my achievements popped.

So for any collectible that doesn't register for you, I would suggest this to finish off your otherwise easy completion and 1k.