I suspect it's there because the purchaser is going to spend a...

I suspect it's there because the purchaser is going to spend a decent amount of money to do the due diligence so will end up spending this sort of money and does not want to be short-changed in case MDR is using the LOI to leverage better offers (or attempt to get competing offers)

I also re-read that, and it does not seem to suggest that this will have to be paid if MDR ask for (say) $70m and both parties agree to walk away as they cannot get to agreement.

It does seem to suggest that this purchase has a 3 mth exclusive period (if MDR are to avoid paying), but if there is a competing bid that is materially higher, then I suspect that MDR will happily pay that amount (essentially reimburse purchaser for costs incurred)