I have stated my point clearly. it happens in movies, books, manga, anime cartoons, plays, hell name any entertainment.
have you never seen where someone tells the person that you will find that if you go to this place. Then when the person leaves someone else is like "how could you send them there, they will die" or the person laughs and goes "well were never be seing him again" or whatever.
They aren't purposely trying to get them killed, they could care less. Allies will tell them the dangers to keep them from going there, because afraid they will die. non allies could care less if they die or not. so they tell them what they need to know and leave out what they don't.
I'm assuming that there is a old jailers place, or he did see someone randomly there sometimes, while you are assuming that there isn't and that he just wants them to go and die. we don't know, but it makes sense that he was telling the truth and withholding the dangers more than him just outright lying to have them just die.