The previous version contained fixed-number shortcuts about striking or scratching. Those have been removed.
The source does not say:
• “a dangerous creature may be struck only 3 times,” or
• “scratching more than 2 or 3 times in one rak'ah automatically invalidates prayer.”
The real framework is the one already studied:
• necessary small action can be allowed;
• pointless small action can be Makruh;
• Amal Kathir can invalidate prayer.
A fixed number should not be invented where the source does not give one.