The only solutions I see here to these first world problems is you should not have bought an R and fire your assistant. If you have enough money for an assistant and like two cards why did you not buy a second R and take the same pic on both cameras.You know these Canon cameras take still photos too, right?
Let me give you two examples:
1) I'm shooting a sports event and I want raw images for post processing, but also want JPEGs for immediate posting on social media; AND
2) I'm shooting portraits at an event, and we want to print quick JPEGs for immediate use, by transferring from a memory card, and also save raw files for better post processing and providing online.
I have had both those happen in the last two months and #2 used my R, but ran into problems when my assistant accidentally deleted the photos of the card that were supposed to have been kept.