Reset sandbox instance

Environment: CRM 2016 with very little data

I am resetting a sandbox instance that has been running over 3.5 hours.  Two questions:

1. How long does it take for a reset to complete for a CRM system with very little data?
2. If other admins login to the CRM while it is resetting, does the reset process wait until they are logged out?

Thank you,

Lannie