Is this going to be a problem . . . . ? * SPOILER ALERT *

[Narkenstein3D]

I saved that Ranger that was bleeding out in Vault 3 and killed the Fiend boss with the chainsaw. I came back to Camp McCarren and told Colonel Hsu that I killed him and saved his Ranger.

Problem is . . . I didn't get that quest to save the Ranger or kill the Fiend boss in the first place technically . . . I found Vault 3 while looking for Violet for the, " Three - Card Bounty " Quest.

Everything was normal until I came back to Camp McCarren and talked to the Ranger I saved after speaking with Colonel Hsu. Apparently the game still thinks he's in that Vault . . .

I also didn't know this was going to happen so I saved way after that soooo . . . . .

Will this break the Questline?

[JokerSmokerMidnightStroker]

you could just use console commands

[LuckyHero]

The Ranger always talks to you like he's still in the vault if you save him before getting the quest, as for the questline, what questline are you referring to? Because there isn't a questline involving that Ranger or the fiends in Vault 3 as fat as I know.

[Narkenstein3D]

I could have sworn when I talked to Colonel Hsu that he said, " I shoudn't have sent you on that mission." I was assuming that I had to get a quest from him or something.

I don't want any of the quests to be broken that's all I'm worried about. I've had experience with broken quests from Skyrim. They're not fun when it happens. :c

[LuckyHero]

It's an unmarked quest which has no connections to any other quests, other than Motor Runner being necessary for a quest with the Great Kahns which is a pretty meaningless quest anyway.
The reward for which is like 100 caps or something in that region which in the long run is worthless.
If Hsu hasn't rewarded you yet, just check in with him and exhaust his dialogue about motor runner, vault 3 and the Ranger you saved, he should give you a reward if you give him Motor runner's helmet and extra for saving the Ranger, other than that there's nothing to worry about.