There are no Christians open minded to the idea that their beliefs are false

Since Christians claim to have a relationship with God, they can't be open to evidence against their existence--because in real relationships, there can be no doubt as to the other parties existence. Through communicative elements, their existence becomes undeniable. You can't be in a real relationship with someone while at the same time concede you may be just talking to the ceiling.

 Real relationships are a two way street, therefore the other "street" must exist. So any Christian who believes they could be persuaded out of their beliefs must deny the the divine relational aspect, or argue that relationships with divine Persons are somehow drasticly different from relationships with human persons.

Edit: typo