Drivers LED door lock button illuminating logic/reason

[G-A-R-Y]

When we get into bed and use the interior locking button next to it, the small LED in the driver's door handle illuminates orange. This usually goes off after 15 minutes. However, I have noticed this light sometime illuminated.
It seems if you use a tap the small light comes on again for 15 minutes, even in the middle of the night.
What is the reasoning behind this function.