Very few are violent. Very few are completely calm. Some cry. Some are verbally abusive. Some try to talk you out of it. Some can't believe it. Some blame other people, including the boss, for their failure to do the job.
But most termination meetings are quick and quiet. If the boss did their job right, the firing wasn't a complete surprise, and if they were kind in the telling, the reaction is usually subdued.
Sometimes people get angry later, which is why it's a good idea to have them leave immediately and to end their access to the building and all computer systems right away.
36 years in HR