Fixes a small bug in ventcrawling that allowed crawlers to avoid things that relied on area.Entered. Mostly the turrets in the AI Core/upload.

Reported http://www.ss13.eu/phpbb/viewtopic.php?f=42&t=9&start=1900#p126318 . NEXT TIME USE GIT.
Merge pull request #3213 from Incoming5643/ventfixer

Fixes a small bug in ventcrawling