Issue with a line for ambushes.. [FIXED]

[Mario98x]

Hello I have a Linedef that should trigger some door, creating an ambush. I did it and tagged the line but I can't walk over that line!
This is the setting:

Edited September 22, 2017 by Mario98x

[Mario98x]

FIXED!! Looks like that a sector is needed to do a walkover thin, didn't know that :)