Annihilation (Movie, 2018)

The plot concerns 5 women entering a dimensional rupture ( The Shimmer) a place where previous teams have not returned until recently ( this is within a 2-3 year period). Natalie Portman plays an ex soldier and current Biologist and the rest of her all female led team have science or emergency backgrounds. In my opinion, they are all young mentally damaged professional women. 

Why did they go into what is almost certainly a contaminated area with no hazmat equipment whatsoever? Why was an "all-female" group being sent in?

At the end, after weird laser lights and body snatcher themes being over, we are still puzzled with not much being resolved.