They can't enter further without wearing the preregistered Pip-boy

The scavengers listened with unease as the raiders thumped against the vault door. If the stories that Jerry had heard were true, they had no need to worry about the raiders getting in. They were safe as long as they were inside and for as long as their supplies lasted. Jerry looked at Jamie before turning his attention back toward the interior.

“Come on, let's move,” Jerry told the group.

They followed Jerry close behind into the vault, and to their surprise, the place was active. Pre-war robots floated from here to there, still doing their predefined routines. Though his thoughts were mostly filled with concern for Jamie, he couldn't help but take note of how many caps this place was going to make them. As they attempted to press forward, they were stopped by a Mr. Handy.

“Stop! I'm terribly sorry but you may not come in,” it told them.

“Please, our friend is hurt,” Samuel begged.

“Only registered residents may enter. Unfortunately, I'm going to have to ask you to leave the vault immediately. I am authorized to use **** if I must,” the Mr. Handy said as his buzz saw attachment began to whirl.

With yet another life threatening situation in front of them, Jerry had to think fast. Using what he know about vaults, he took a gamble and ran back to the pip-boys. He snapped one onto his wrist and grabbed three others.

“Put it on,” he said, passing one to Daniel.

Jerry snapped one on to Samuel and the last one on to Jamie. Jerry turned back and held up his arm and yelled back at the aggressive Robot.

“We are all registered residents of this vault. Stand down!” Jerry shouted.

The Mr. Handy's saw came to a stop and his arms lowered. They all let out a sigh of relief before hearing The floating orb speak again.