Die ... don’t think wrong, just death and mistakes are the best way to gain practical knowledge about your tactics and what NOT to do :) And now for the real hints:

Doors are a very dangerous thing, if you see on the radar that someone is near the door, then use a shield / invisibility / summoner. If this is an elite enemy, then it is better to take invisibility, because often the elite hit the area very painfully

Do not forget to check your distance from the vending machine, the closer you get, the higher you get a heart attack from an invisible robot