Looting Isn't Worth It if It Gets You Killed
This game isn't Diablo (though it can feel like it sometimes). The general behavour of many players it to move towards the sounds of a fight. Its where the action is, right? That means the longer you are in fight, the greater then chance another person is somewhere in the peripheral waiting to shoot you the second you let your guard down.
Don't let that guard down!
I know all that juicy loot in that field is beckoning you to run your hands through its golden hair, a siren calling to you, promising love and naughty things your parents don't want you to know about.. but its a lie!
Look around. Make sure its safe. And if you don't think it is... just let it go.
Don't be that guy, you know who I'm talking about.. the one that walks immediately over to the guy he just killed, stands still while shifting through the loot.. then gets shot in the head.
If you are truly desperate, just run by, grab the purple stuff without entering the inventory screen, then find cover to sort through the mess you've grabbed and hope you haven't accidentally switched out your favorite weapon.