I just noticed that I can’t really run the programme twice and just set 0 to the lowest point of the first pass, because my Z travel is only 3mm. If I want to go deeper than 3mm, I have to create another, identical programme except that I choose the starting layer to be 5mm in Estlcam. So my 0 stays exactly the same, but it starts 5mm deeper. That way it lifts the Z 8mm instead of 3, then it works again. Luckily this thought occured to me while taking a break after milling the first pass. Phew. My 6mm endmill would have ripped it to shreds… 
Here is the current WIP: MPCNC Primo Schneewittchen - Oldenburg, Germany - #116 by Tokoloshe