When First confronted with a survival situation, The first thing to do always is to ASSESS your personal SAFETY within that time and space.In order to react to save your Life, you must first determine what the threat IS that you need to react to. First and foremost... NEVER PANIC. Panic Kills... simple as that. Never react BEFORE you know what the threat is... and never REACT until you KNOW what you need to accomplish. Doing any of these would be completely ANTI-survival!
Determine the presence or absence of threats to your safety and well-being within and from your surroundings. Scan All around, using ALL of your sense's. Look, Smell, Listen, Feel, taste... even sense for any uneasy feelings or spine tingles that could indicate a threat is near you.
Always start scanning closest to you, scanning all around... then out a little further... then a little further... and so on. The most immediate dangers are often (but NOT always) with in 3 feet... which is also your best effective range for self-defense hand combat techniques if required.
Determine Fight or Flight. The best rule here is to fight if the danger is within 3 feet and CAN be fought, such as a wild animal bearing down for example, and there is no choice but to do so. If you ARE required to act against such a threat, it should be done the moment you identify the need... without hesitation, and with creating an escape path to Safety as a primary goal, and lethal or severely injuring techniques are the best tools to accomplish it.
A note on retreating to safety: be it after fighting to create an "escape" path... or from an oncoming overwhelming force, as soon as ANY threat is identified... the next thing that MUST be determined is WHERE SAFETY IS.
Sometimes there IS NO such PLACE, and you MUST fight for domination to survive and escape your current environment, but usually you can find a place with enough distance or obstruction, concealment or fortification where you could relocate to and be AWAY from the presence of the threat. Sometimes if it's just a single animal or attacker... you Kill it, and Safety is where you stood all along. Other times you have to create an escape or just flee all together, and safety may be 3 feet to the left, or on the other side of the nearest Mountain Range.
However you Must identify this place in the presence of danger, and what it will take to get you there, and focus on it Like a problem and NOT stop until you "solve it" and find yourself in a safe Location. You must find it to be effective in combat at creating an escape route (the goal of fighting should ALWAYS be to STOP fighting!) and to even be able to consider long-term survival needs. Short Term survival ALWAYS Trumps Long term. Without short-term survival... there can be NO Long term survival. Specific defense tactics will be discussed in a later addition.
Something else worth mention, while discussing threats like animal and people attacks and even natural disasters. It helps to identify threats AND to know how to react to them by categorizing them by type based on WHERE specifically the threat is COMING from.
An Immediate Type threat COULD come from:
*A Human Attacker (within 3 feet or possessing a fire arm or other long distance weapon would be "immediate")
*An aggressive or poisonous animal or insect (depending on the animal or insect, anywhere from 1/16th of an inch to twenty feet could be considered an "immediate" threat)
*The Ground (treacherous footing, sinkholes, quicksand, Land Mines, anything but good old solid terra firma could be considered an immediate threat. Also it should be STILL... If it's shaking you may have need of some form of shelter. If ONLY the part you are standing on is shaking... MOVE!)
*The Air (Poor oxygen supply, presence of gasses or chemicals or radiation, fluctuations in barometric pressure)
*The weather (Hyperthermia, Hypothermia, High winds, High water or waves, Flash floods, Lightning, sand storms... ect...)
*Natural Or Man Made Disasters (These could include anything from a dangerously close volcanic eruption to a potential for collapse of the building you are in due to rot, damage, or poor construction, or even approaching gunfire and explosions. And yes, I consider War to be a man mad disaster.)
*Bleeding wounds, breaks or infections. (Don't underestimate these or just "assume" they would be self-evident. You would be AMAZED at how much the body can be damaged without the mind realizing it if the adrenaline is flowing... and the resulting euphoria would make you feel like you were "just fine"... so it's always important to assess your body for damage as soon as possible.
Don't just LOOK for cuts and possible fractures... but FEEL for them. Rub your whole body, periodically checking your hands for blood smears. Again don't just look... Lick your palm if you have any doubt. If it tastes like iron... there is blood there. Sometimes it isn't possible to see, and even when it is at times the eyes can play tricks... so never trust them alone. Always use a second sense to confirm, not just in survival, but in ALL things... before you accept any idea as an actually fact of reality.
Also put weight on everything that is ment to hold weight and see that it does. Stretch every which way, bend and flex every joint and be SURE every thing works... nothing is missing... and nothing is leaking. Maybe even take a moment to listen for your heart beat, feel your pulse... or focus on breathing in and out... just to be sure you are really alive. No point wasting time surviving if you are dead all ready...
Then check again for any older wounds that may be infected, and take note of any internal symptoms you may be feeling like nausea or headache, as all of these will need to be dealt with. In the wild even the mildest illness or infection can be lethal if left untreated, and will hinder your performance at survival in the mean time.)
If ANY of these threats can be identified... it is important to move to safety as soon as possible. Fight or Flight... either way do what you MUST to get to a time and place where NO immediate threats can be identified. You will STILL be in the open and in the wild most likely, so this place isn't necessarily going to be TOTALLY safe, as new threats could always approach, but you will at least be safe in the present tense... which is always the FIRST thing to look for. This spot will now be known as your Preliminary safety zone.
Obviously the first quality it should have is the absence of any immediate threats to your safety or well-being. Aside from that, it should be well concealed from threats that may be passing by... not out in the middle of a field or sky-lined on a hill-top if you could help it. The half way point up the side of a long ridge which stretches a while each way would be ideal for this, as you are not skylined, have a decently Long field of view if the hillside is big enough, with equal reaction time to threats both above and below... and hopefully with a good long-range field of view in all directions to see approaching threats at as great a distance (i.e. with as much reaction time) as possible.
If that can't be found... try to find a spot that has similar qualities of both ranged view and close in concealment. If the spot also has natural or discarded man-made resources you may be able to scavenge from... even better.
Also be wary of the time spent looking for a spot, and the exposure that comes from your movements. Stay as quiet and concealed as possible as you move, and follow the path of least resistance (Unless you think you may be being followed by some one or thing perceived to be a threat... in which case following the path of GREATER resistance can help make your movements unpredictable while also placing difficult obstacles where ever possible between your self and the pursuer.
Remember this is a temporary spot, and it doesn't have to be perfect. Just be sure you are safe in the present. You can deal with every thing else from there.