The episode in its entirety was very well set to the time period but goes gravely amiss in the resolution of the problem.
The "map" of the blood came from a Knight now dead a 1000 years. So that blood has been in that same spot for 1000 years , why the heck would you go out there in the middle of a bloody battle to retrieve it whilst you can time travel and visit that same area anywhere in history for the last 1000 years and pick a nice day for a stroll.
Usually the time travel is used rather well as a plot device, just not this time.
The "map" of the blood came from a Knight now dead a 1000 years. So that blood has been in that same spot for 1000 years , why the heck would you go out there in the middle of a bloody battle to retrieve it whilst you can time travel and visit that same area anywhere in history for the last 1000 years and pick a nice day for a stroll.
Usually the time travel is used rather well as a plot device, just not this time.