There's a certain weight off her shoulders even as fear sinks its first cold tendrils into her. A long time meant the human race wasn't gone. A long time meant they'd had time to begin with. Octavia had lived; that meant the bunker wasn't destroyed. That meant she'd survived as leader; she'd have held them together. Clarke doesn't doubt that much for an instant.

"I was supposed to be headed back to the Ring, but they needed someone to stay behind to activate the transmitter. I took too long. I made it back to Becca's lab, and then -- here I was."

Miraculously not dying or even recovering from radiation poisoning, thankfully. It would've been a miserable few days even if she's pretty sure she would have woken up.