ᐅ How to Best Connect a Katja Sprint?

Hi, due to increased radon levels (not really a lot) in our region, it is recommended to install a Katja waterproofing membrane on the ground slab for new constructions. My problem is that I would like to do the electrical installation, IT cabling, etc. myself directly on the ground slab. The issue is that if I lay the cables on the Katja membrane, I risk damaging it by drilling or fastening. I have talked to my brother-in-law who had the same problem, and he solved it like this (see picture). However, what I don’t understand is how to connect the Katja membrane to the damp-proof membrane above the base layer? I have made a small drawing and marked the spot in red. Maybe someone from the forum can help me with this? To connect the Katja in that area, the plaster would actually need to be interrupted at that point... Or maybe it is enough to simply extend the Katja slightly up under the plaster (I haven’t checked yet if this is even possible). Or is it sufficient to accept the small gap between the Katja/plaster/masonry (since the waterproofing is only intended for radon protection)?