I've use it since I started flying these things and I promise you it will turn and come home when you hit RTH.
Just say you are on flat ground .
If you are below what you have set say 60m it will rise first to that then come straight back .
If you are at 120m it will just turn and stay at that if you let it till it gets overhead then land.
If that don't make it clear I don't know what will other than using it and like Meta said not practicing with it and trusting it will get you in trouble.
But let me say this . I have mine at 40m . I went down a field about a mile at 20m and the field took a left .I continued down that field and lost contact . It did rise to 40 m but there was a hill between it and me and was more than 40m .Had I not made contact in the app I would have hit the trees on it but saw them in time to rise above them so just be aware of whats between you and the bird ,being a pole ,tower or whatever . Hope that makes it clearer .