[Kobal2]

You should also know that each Lantern has a vanishing chance of giving the researcher a single Mark, which in turn only translates into a 2% chance to get horror'd every turn. As long as you check your researchers every turn, take the Lantern away from the guys who got marked and pass them on to a new guy, they probably never will get a meeting with their fate.
If you're not using horrors in actual battles (through the Call Horror spells), then you can quite safely rotate the marked researchers to combat or communion roles. Once in a very, very long while you'll get a nasty surprise, but not often enough that you'll even notice it.

On the other hand, called Horrors do home in on marked characters first and in my experience they'll then keep attacking the nearest mages so never call a Horror if you have marked guys on your side.