Would Dentist usually fire someone in the beginning of the day or the end of the day?

I am worried about being fired from my dental office I work as a dental assistant and I am trying to prepare myself in case it should happen. On my contract it says the Dentist can fire me without any prior notice at any time. But is it more likely the dentist will tell me in the morning and then I can still work the rest of the day? Or would it be at the end of the day? Or would it be by phone or email? I'm just wondering what the average Dentist would behave in this situation?