Any suggestions for removing internal cable routing guides on a BMC SLC01?

I want to enlarge the entry holes and run my Di2 wires inside the frame but the internal routing guides for traditional cables prevent me from simply enlarging the holes and inserting the Di2 wires. Do you think if I just both holes on either ends of the guide that I could simply pull it out? Or are they also attached somewhere along the way inside the frame?

The last thing I want is broken guides floating around inside my frame. Anybody ever seen the inside of an SLC01?

Anybody have any thoughts?

Where would be the best (least stressed) spots on the frame to drill exit holes for the front and rear derailleur Di2 wires?