Well, there is good news and bad news.
The good news is that you don't die. As long as at least one available character, except for the current one, has more than 0 health points, the game continues and another character with enough health points to continue the game will be available to you. If the number of health points of all available characters drops to 0, the game will evacuate them to the base for recovery.
The Base itself, Base facilities, the level and skills of your character are not affected by the evacuation!
The bad news is that after the evacuation, the character's inventory will be empty. Only what was in the pockets of the characters will be saved. You can try to return to the evacuation point and collect your belongings.
Evacuation point with the items from the backpack is showed with a special icon on the map. Wouldn't you risk to return for your stuff?
You have the option to save your loot from the backpack by using C-coins or by watching an ad before evacuation.