It has been suggested that the whole thing was a plot to get Rand addicted to the TP. I don't know if this is true, but using the TP certainly made Rand way darker and nearly gave the DO complete victory at the end of TGS. BS has also implied that there may be further negative consequences for Rand's use of TP.

So it may be that rather than being upset, the DO will instead be quite pleased with Moridin for managing to get Rand to touch the TP. Assuming ofcourse that it was the link that was responsible and that the whole thing was not by DO's design in the first place.

Still, you are right that whatever happens with Rand and TP and the consequences that come from it will be interesting. I hope so anyway.