THe purely physical effects are simple enough to trigger; rapid breating, adrenaline, rapid heart rate, etc. However the tunnel vision, the fear, the mental physiology, the brain chemistry cannot be simulated nearly enough.

What all of us do is called "practice" for a reason. With enough of it you hope to have simulated many difficult things which are very difficult to cope with... but by attempting them, exploring them can be dealt with more effectively

It's "lifetime practice" for excellent reason! We age and things will change, requiring adaptation on our part. To get, and explore your adrenaline response... the invention of Sanchin kata comes to mind ; ) as a wonderful tool to at least ~flip the switches~... start adrenaline coursing through your body.