Well, it's possible to stand a critical single shot with those stats and perks, but not a burst, luckily that chance is very small, as I said. If you get knocked out by a critical single shot at the first moment in a random encounter, with 10 Endurance you'll get up immediately, on your turn, being able to move away if necessary and sneak. If the enemy has a Minigun, it's 600 Dmg.

It's recommended to have this amount of hit points, around Level 30, before making the trip. A special case is when you go to Navarro, an Enclave patrol will fire 2 times in the first turn, with a Pulse Pistol this means like 370 Dmg. So a critical from a Plasma Rifle can do 260 Dmg. The normal 'must have' perk is far less important, as you have all the time to kill. It's hard to delay Bonus Rate of Fire, but it's necessary. At level 24, the Chosen has like 300 HP with 10 Endurance and both Lifegiver ranks, taken at level 12 and 15. The good news is that will happen 1/5 (most groups have 5 enemies and only one has a burst weapon) * 1/20 (their Luck and Critical Chance) = 1/100 of times or 1% chance, a tiny one. weapon Dmg divided by 3 b/c is at range (when someone uses a burst weapon and he isn't next to target, around 2/3 of bullets are wasted) and multiplied by 4. From a burst weapon, like a 10 mm SMG, this unfortunately means 160 Dmg: 120 max. This can happen often enough, because many enemies use targeted shots. A critical hit from a single shot weapon, like a Hunting rifle, which bypass your armor, can do 20 * maximum 4 times the normal damage = 80 Dmg. At level 12, you'll have around 120 HP with 10 Endurance - this stat is a must, see below. You can always survive to one attack, even critical? Melee baddies aren't a problem, they only have action points to reach you. Will always happen and you can't avoid this even with the maximum Sequence (10 Perception, Kamikaze, and 3 levels of Early Sequence perk).The only way to act first is to keep pressing A as the map is loading, but it can be considered an exploit so probably means no Ironman anymore. Second, no matter your Sequence, only one enemy will have his turn before you. At 150% (tagged), maximum which makes a difference, you can choose around 75% from the encounters. First, it isn't possible to avoid them all, even with 300% Outdoorsman, Survival/Ranger perks and a car. Unfortunately, you can't avoid being hit by ranged weapons in random encounters, but you can make sure you won't be killed (Sneak will stop when you enter a new map). Sneak is a must for an Ironman and ,BTW, heavily recommended when playing as Unarmed. Having Sneak with a party is useless, it's almost impossible to babysit their bloodlust. Guess they don't like bothering with small people :) Then, you can't sneak, no matter the distance, and thus you'll be hit until that specific enemy or the NPC is dead. Why you can't have a team? Enemies ignore party NPCs, even if you start the combat, until one NPC fire the first shot to a baddie. If you just wound someone in your turn without killing him, end the combat and start it again,otherwise he seems to know from which direction the bullet came from and he'll shot you. Also you can stop the battle at any moment bearing the mentioned distance if doesn't work on the first try,hit Spacebar for the next turn and it'll be possible this time.

Fallout 2 small guns