What resets your personal damage counter on blackwyrm?

[NimbleVolunteer]

I would like to know any and all things that reset the contribution you do to blackwyrm. Basically anything that determines whether you get valuable drops or not. 

 

Some things I'm wondering about: 

1. Dying and respawning

2. Leaving combat (and for how long)?

3. Going down and resurrecting through meditation