You don’t have to wait to use deadly force to defend yourself when confronted by a deadly force situation. The standard is a reasonable person standard. Thus, if you are about to be greviously injured or killed you may respond with deadly force to protect yourself or others. See my video below.
In Oklahoma, the standard for using deadly force is the reasonable person standard: See my video
There are overlapping, Federal and State Laws regulating the carrying of guns in school zones.
Depending on the Casino, if it is owned or leased by a governmental agency, you cannot carry. If the gambling operation is on private land, the owner or operator may allow concealed or open carry on the premises.
Keep calm, advise the police that you are armed and follow the instructions of police related to producing drivers license and conceal carry permit.
Take a few minutes to listen to my commentary about using a firearm to back down an adversary or using gun to influence another person to leave you alone. Your actions may have severe legal consequences.