Ask any of them: "If I ask another person, which one will he say is the dead door?" Then both of them will point to the door.

For example, if you ask a liar, he will point to the door of death, because he will tell the truth, and if he tells a lie, he will point to the door of birth.

For example, if you ask the truth, because the liar will tell a lie, he will point to the door, and the liar wants the truth, so he will point to the door according to what the liar says.