I'm not an expert, but I believe that the term sheet for M&A normally includes breakage clauses, so that the acquirer has to pay the target a breakage fee if they pull out of the deal without a really good and previously agreed reason.

If you don't have such a document in place, you should probably not agree to a DD. DD happens after everything is negotiated, as a final formality, not as a precursor to getting everything agreed.