Better offers can be made, they must notify TPG to allow them to increase there bid, whilst the reading implies none will come the following is in the document and leaves the door open to a better bid
"Bidder acknowledges that, subject to the other terms of this agreement, each (c) Target director may publicly (or otherwise) withdraw, change or in any way qualify their Recommendation or Voting Intention if: (i) there is a Superior Proposal"