When did Robin become so evil?

I walked out of the practice room with Kate, we didn't get to practice anymore because of what had just happened earlier, which also shows me how important Katherine was 8n this whole situation.

Ryan knows her and ran after her, Hinn who is supposed to be my boyfriend also went after Katherine without glancing my way, and Robin’s eyes darkened when Hinn Carlos ran off and the three boys were friends too, this means they knew what was going on.

"Why does Katherine hate him so much?" Kate on her own was trying to figure her suspicion out by thinking aloud which also interrupted my thoughts.

"Hey, Kate." I touched her shoulders and she looked at me. "I will be right back, okay," I told her and turned to go.

"Where are you going?" Kate called out but I rushed off without looking back. I was going to find out what was happening and why my boyfriend had to go after Katherine.

I didn’t know where to go find them so I headed to Katherine’s practice room, this was the place I usually see her s