To his credit, Strange does look a little apologetic as Lambert leaves the room. That apologetic expression is on his face for a few moments before he feels Peridot scowling at him and Strange quickly adopts a scowl of his own. He's fine! He's not sorry about his actions, he didn't goof up, he is entirely perfectly fine with how things went except for the fact that he really kind of isn't.

"It should," Strange admits, as he gently sets Pumpkin down on the ground. Almost a moment later, she starts whining. "The spell I use can easily be modified to include a sympathetic tie, especially one as small and personal as this feather. We'll need a large bowl of some sort, like a mixing bowl, filled with water. Likewise, I'll need pencil and paper so I can write down the incantation--you'll say it, while I perform the actions needed, thereby linking our power together for the spell."

It certainly sounds like a lot of impressive magical bullshit, at least. And fits in with any theory that Peridot's read about multiple people casting spells and/or scrying.