Disable teleportitis when reading spellbooks
As it is nowadays 100 % possible to continue reading spellbooks after a random teleport event, it is in effect only a nuisance. I can't think of anyone wanting to interrupt a spellbook reading because of a random teleporting. Therefore, I suggest that it should not kick in at all while reading books.
The current behaviour is also not in line with other activities using up many turns. Random teleports never occur while fletching, smithing, eating, cutting down trees, mining or writing scrolls. Why should it happen when reading spellbooks?