Enrage and damage calculation mid phase
No, all damage is dealt simultaneously. 


  
  Combat Damage Step
  
  
  
    510.1. First, the active player announces how each attacking creature assigns its combat damage, then the defending player announces how each blocking creature assigns its combat damage. 
    
    510.2. Second, all combat damage that's been assigned is dealt simultaneously. This turn-based action doesn't use the stack. No player has the chance to cast spells or activate abilities between the time combat damage is assigned and the time it's dealt.
  


This would only work if the creature blocking Bellowing Aegisaur had first strike or double strike.