Depressed people often deal with intrusive thoughts. The last thing you want is someone lying in bed, alone, while everyone else is asleep, entertaining those thoughts.
One of the archetypes of depression+sleep disturbance is people staying awake until they are absolutely exhausted and then collapsing into a sleep that the apocalypse could not rouse them from. That’s not a bad habit, it’s a coping mechanism.
that deep sleep you described is something else... it's what I call my petit mort (and yes, that's an intentional misnomer).
I now actively try to avoid using that turn of phrase, and when I catch myself about to say/saying it, I check myself and remind myself that I'm also susceptible to this blind spot.
The old adage, “the worst beginning to a sentence is, ‘Why can’t you just…’” is something we understand viscerally. Seemingly doesn’t stop us from doing it to others.
Try to maintain composure for as long as possible.