That $1 million, is only for the purchase deposit, of which Aersale gets to keep if Baltia fails to close the deal.
Paying for the C check is a separate expense, that is part of the Aircraft lease agreement, not the purchase agreement.
If for whatever reason Baltia is unable to close the deal, they will have no need to lease N417XA and not have to pay for the C check. The plane will remain in storage, most likely to be used for spare parts.
As per the agreement: Proof of funds will be made available to the Seller 15 days prior to the Scheduled Closing Date.
Presuming they did provide proof of funds we're left wondering if the FAA will allow the transferring the authority of Songbird's certificate to Baltia.