You ended up in Kamar Tarji because you couldn't control your powers, you pretended to be your mentor with Doctor Strange, you always had a unique and special relationship with him... maybe you think too much...

One day you were talking to Wong, about the full moon party you were not doing anything wrong but you see Stephen with a look that wanted to strangle Wong, and he grabs you by the arm and says to Wong

Stephen:"Excuse me Wong, but I have to speak to my student"

Stephen pulls you in with a jealous look, and takes you aside and looks at you with a super jealous look

Stephen:"you don't need any mentor just me...ok? I'm your only mentor! I don't want to see you with anyone else"

he says all this raising his voice a little