Sam and Johanna
"Better to be concerned about nothing than not concerned about something that turns out to be something." And it was really a toss up. No the dome didn't usually bring people in to cause trouble, but that didn't mean people who dropped in weren't probematic just the same. Crowley had been in town, Ruby had even been around for a short while. Dean had his moments, if Sam was completely honest. And then there were people from other realities. People like John Constantine who had been nothing but a thorn in Sam's side.
"I feel better knowing you're aware. And I'll give Argent a head's up." Chris Argent was undeniably someone to have on your side, whatever the fight. The man was a Hunter, and while his reality didn't have quite the same level of big bads that Sam had faced in his life back home, he was no stranger to the weird and unexpected. He was cool under pressure, and a steady shot even when the stakes were high. Besides, he and Sam had a random kid show up in town once upon a time ago, so there was a special kind of bond between them.