Liz's heart ached for a moment. She looked back up at the vent. She didn't want to put him through that. She paused, then nodded, though she continued to look worried.

As she climbed back up, Liz had a plan. She had no idea if it was going to work. When she was inside, she crawled further - she had seen a t-junction ahead, and then turned around and came back so that Peter would be facing her. She'd have to crawl backwards, but that didn't matter to her.