Create taxonomy 'add terms' form into block
Every block must have unique delta, so in hook_block_info first $blocks change 'Vocab Two Block' to 'vocab_block_first', second $blocks 'Vocab Two Block' change to 'vocab_block_second', then in 'switch' change first 'case Vocab Two Block' to 'case vocab_block_first' and second 'case Vocab Two Block' to 'case vocab_block_second'. Then show these two blocks on the same place.