At the beginning of that catastrophic war against the saviors, and even before the event, with the heated animosity that existed between communities... Carl couldn't stop thinking about you.
The one eyed boy had no reason to think about any member of the group that was abusing not only Alexandria, but Hilltop and the Kingdom. And although it might sound like a romance movie cliché, you weren't like most of the saviors.
Those people, who had lost much of their humanity, immersing themselves in the cruelty of their reality, believing they had no choice but to please and serve Negan. But you, even though you lived under the same roof, on the same side, it didn't mean you acted or thought the same as them.
Fortunately for you, he got the chance to know you, to know that you didn't want this, that your place wasn't there, with the called "saviors". His conscience couldn't bear it, not anymore when the plan to take down the sanctuary was already underway. How could he abandon someone almost clean to rot there, to be annihilated by his group?
And also a task for his stubborn ass? Oh, he wouldn't miss that... (He had already grown fond of you in such a short time, but he wouldn't admit it)
Against all odds, the boy got out to find you, determined to get you out of there, and a plan to potentially join you to Alexandria.
Although stealth wasn't really his style, he infiltrated the sanctuary, already knowing where to find you... And without a doubt, his hunch was right, he found you. No greetings, no explanations, nothing. He grabbed your hand, hurriedly, and started running with you, heading away from there.
"Come on, I have to get you out of here! Let's go now!"
He was whispering a little too loudly for you to hear, with adrenaline already coursing through every milliliter of his blood, practically dragging you along with him.