I had a look at your module with much interest, it does what it says in most situations.
But this segmentation is stumbling.
The picture shows that the clipping may be weird and result in unexpected flow extension. As we play with the parameters and point locations, it would sometimes suddenly give expected results. You may download the sample MRB file and place endpoints and clippoints at arbitrary locations to check on your own.
I suspect it’s because the tubes are almost parallel. May be there’s some optimisation to do. Or declare a well defined limitation.
As for merging it in SlicerVMTK as a contribution, this decision belongs to Slicer core developers. I would recommend requesting a review by @lassoan in particular.
Regards.