Well, are you sure that these cards were placed in the first aid kit seeing as these kits are usually sealed unless it was used on the flight. As well I dont think it would hinder an f/a that much to open the kit to remove the cards to get something like gauze. If there was a serious problem then the doctors kit would have been used and not the first aid kit seeing as the only thing that is stored in those kits are things used to wrap cuts treat burn etc.
Using the first aid kits to store these cards would be more work then what it is worth. Are you sure it wasnt the documantiation container, or a container that housed these docs?