What was the point of time travel? The ones left behind did nothing but to retrieve the sword everyone knew was left behind unprotected in Deidre's mountain and renovate bathrooms and showers and modernize the kitchen. They didn't even care to contact the druids at Isle of Eigg and convince them to become the protector of the tablet. They knew there would come a time they have to face Deidre again, but in 400 years they just sat there in their castle waiting for the warriors they sent to the future to come back, and they did just that. They got the the future, they started walking back to the castle except for Logan.