A critical incident or emergency situation isn't an isolated happening, it has a wide array of factors that are changing rapidly. On the other hand, the training that most police officers and law enforcement officials receive is isolated. For instance, when they are training marksmanship, that is all they are training, and when they are learning about de-escalation or use of force appropriation, that is all they are training. In most cases, police officers don't get an integrated training experience that allows them to use all of the skills they have trained and improve their decision-making abilities under extreme stress.
Stress can be very impairing to a person's reasoning skills, and any critical incident brings high levels of stress with it. The only way police officers and first responders can make sure that the stress of a critical situation does not affect their performance, and duty is to have experience in such situations.
The most effective, and practical way of preparing for critical situations, and pressure testing all of your skills in a realistic and safe environment is to use training simulators. Modern training simulators are designed to offer hyper-realistic training scenarios to police
officers, first responders, and civilians, which allow them to test their skills, and learn how to use their isolated training regimes in a fully integrated and responsive environment.