User blog comment:Rainb0wSprinklz/Problems with the final confrontation between Granny Rags and Slackjaw/@comment-27202257-20121231214149/@comment-27202257-20130101071822

It does not count as an automatic detection as long as you get the heck up out of there before Bend Time ends. If Bend Time is not in effect when you grab the key, it will be an automatic detection, but as long as that's in place, you should be fine.

Also, I had the same concern, but was able to go all around the room and nab everything of use without her coming in after me. If you're concerned though, the escape hatch is right beside the door, so you can quickly break it open and get swept out of the area. She definitely won't follow you after that.