Reusing a spline in a loop for trim operation

[roldy]

I have a spline where I need to create a line tangent to the spline curve in a particular portion of the spline. My work flow is to create a copy of the original spline and trim it between the boundary lines which I select using the loop counter. Since I now have a segment of the original spline, I'm able to create a line tangent to the spline in that loop interval. The problem I'm having is that when I get to the second interval, the loop is referencing the segment of the spline instead of the original spline. Is there a way to always select the original spline? I'm working on SolidWorks 2018. I've attached the Macro and the SolidWorks file I'm using as a test.