You actually need more training then you would think. this book is pretty good if you are interested.
http://www.barnesandnoble.com/w/the-disaster-diaries-sam-sheridan/1111672403?ean=9781594205279
keep in mind that staying safe and healthy is one of the most important things. a broken leg or bad cut could probably kill you or limit you to the point you may not survive
how much ammo for the mp5? because otherwise its useless