In an EC135 if you get a LOW FUEL on the Warning Unit (red light and audio attention getter) you land within 8 or 10 minutes. This is a memory item.
The LOW FUEL indication is independent of the fuel quantity indicating system and should be acted upon regardless of the fuel quantity indicated.
So if you have mismanaged the situation the red warning (one of only nine) catches that and you act accordingly and sort yourself out.
Fairly simple?