How are you getting the point w.r.t SplitContainer? You can convert the client coordinates of one control to the client coordinates of another by using Control.PointToScreen then Control.PointToClient. For example, if you SplitContainer object is named "splitContainer" and your Panel object is named "panel" then you'd perform the conversionlike so:
Point screenPoint = splitContainer.PointToScreen(point);
Point newPoint = panel.PointToClient(screenPoint);