The light stays on for 60 seconds or less, though it is bright, so I'm glad my unit sits on the floor beside the bed.
If I had to have it up higher I would ensure the display was either shaded or facing away from me.
I can pretty much see in the dark, so the light going out before I get back to the bedroom from a wee walk is not a problem.
My wife has lousy night vision, so in motel/hotel rooms I leave the bathroom light on with the door slightly ajar, just enough to give her a bit of light to find her way around the strange room.. I also carry a torch in my "travel kit" to keep beside the bed in case the room has no bed lamps.
The unit, DreamStation is advertised as having the feature to sense the light in a room and dim the LCD screen accordingly. I've had this unit for a few months. Mine has never functioned, i.e. the dimming feature of the LCD screen. This is the only issue I've had with this unit. I covered the screen as I find the light too extreme at night if I need to disconnect for whatever reason. When I realized that this was a malfunctioning feature I called my DME. This unit cost a lot of money. My insurance is expensive. This unit should work as promised in every way and this a feature I want to function perfectly. Before I take complete ownership of this unit, I will figure this out. My DME didn't know about this feature. I'll report back as I have read that others have the same concern.
It is not your unit, none of them have this working, AFAIK. It it likely a software defect.