Do not stay until the last flight if you only have a purple body armor on and you are playing solo, it is extremely risky and not worth losing all your loot. A single well-placed grenade literally can instakill you like I did to the poor fella you can see in the screenshot. And yeah, if you are the one who's gonna get inside the chopper, make sure you throw a 'nade inside just in case. If you unlocked at least legendary body armor, put it on right away, it is a nice upgrade over the epic one.
As for other things, there is a serious survability difference between the mythic and the legendary body armor so, if you often play hard, don't be cheap and always run with the mythic one. While we are at it, your weapon should be legendary minimum. I have killed players with legendary or mythic body armor whose weapon is… Epic (10% less damage to legendary armor and 20% less to the mythic one).