After Zelda finally let go of him after exactly the same amount of time Nadine had. Tyler knew he didn't have any time to waste or come up with a decent plan so he decided to improvise. He made quick decisions based on the information he had on hand right now, he didn't have to worry about the undead army for a while as it would take them at least a week to March all the way to the eastern parts of the darknar forest so all he needed to do now was deal with the ones attacking the castle.
There was no way it would be one of the Great Five as if that was the case, Tyler was sure Albert would've died without a chance to contact him. Moreover, they would've been cautious brought to set up an anti-communication barrier around the castle just as a precaution so the other Great Five families wouldn't be able to interfere.