How did she turn around in the pipe?

That was for me too really implausible, and took me right out of the moment. Brilliant scene, if only the director had taken a minute to show her crawling to a junction with more space where she could turn around and come back. That would have also underlined how narrow the pipes were and made the whole thing more claustrophobic for Gorman.

She had approached a Y connection and she was able to turn around there.

++++++
Love means never having to say you're ugly. - The Abominable Dr. Phibes