I think that the escape maps have some special escape zone for the Terrorists too, I don't know its name exactly but on the VIP maps the escape zone is named "rescue_zone", maybe in the ES maps is something similar, better open the map with Hammer Editor and see for sure what is it.
EDIT: The "rescue_zone" is for hostages but I found what you are looking for:
For Escape maps the entity is "func_escapezone"
For VIP maps the entity is "func_vip_safetyzone"