Problem: as soon as you go in the building in residue processing there is a security guard, head crabs spawn, and he dies, i wanted to save him so i ran up to him preventing the head crabs from killing him, he ran away straight into a barnacle, how do i save him?

Step 1: quick save as soon as you see him

step 2: run in front of him and don't let the head crabs kill him

step 3: he will run, run at him and right before he gets eaten by the barnacle hit him with your crowbar and jump into the barnacle

step 4: he will stop, then kill the barnacle as you get sucked into it

step 5: once you fall the head crabs you didn't kill will have started to attack, kill them

Step 6: you did it! For a little while he won't talk but you can press e on him to tell him to follow you or not

he doesn't have a weapon but if your in the mood to save a life have fun, took me about 15 tries.