It is easy enough, if you want one column for your answer:

DECLARE @Questions TABLE ([ID] int, [Question] VARCHAR(64))
INSERT INTO @Questions VALUES(1,'Q1'),(2,'Q2'),(3,'Q3'),(4,'Q4');

DECLARE @Answers TABLE ([ID] int, [Answer] VARCHAR(64))
INSERT...

Some of the poor performance is down to your xpath and the use of both .vaue and .query.

This is somewhat quicker. (Though it is never going to be as quick...