$self->run_modes(
  start  => sub { shift->_runmode('start'); },
  middle => sub { shift->_runmode('middle'); },
  end    => sub { shift->_runmode('end'); },
);

# ...

sub _runmode {
  my $self = shift;
  my $html = shift;
  my $dbh = $self->param('dbh');
  #....
  my $tmpl_sub = $self->load_tmpl($html . '.phtml');

  #...
}