Typically, a shooter in the weak side corner will not be closely guarded, on the theory that if the ball is passed over there (over the heads of the defense), it will be in the air long enough for the defender to get there, and the defender doesn't want to get out of rebounding position or leave the lane open for a drive by someone else.
In this case, though, the inbounder could make a low line-drive pass straight to the shooter, so that general principle didn't apply. Aaliyah should have recognized that and gotten in that passing lane (while staying inbounds), or she should have been closer to the shooter. It was just a mistake, reflecting her inexperience in guarding that kind of play. At least that is my opinion.
However, I will bet that Indiana had a play ready where if Aaliyah had vacated the lane to cover the corner shooter, they would have hit someone else for a layup, exploiting the vacant defensive position in the lane. It was a good play, probably designed for that specific situation.
Even so, Aaliyah recovered enough to get out to the shooter and force her to make a move to her left to get a clear look, increasing the difficulty of the shot. She hit it anyway. Indiana earned those two points.