When you use the response to char response statement in a block, be careful to ensure that ESL knows when no more information is expected, so that all available responses, including those outside the block, can be taken.  In order to check for a pattern match in an outer block, the pattern in the inner block must not be matched.  When you are using response to char, the only way to do this is by using a specific pattern match that excludes any other input.  Specify the column position in the match clause (described previously) to make sure that all available responses can be taken.