It depends on the mixer manager's fear and the extent of his feeling that the police may knock his door or initiate a lawsuit against him, or is in a country that can extradite wanted persons to the United States, all factors that may suddenly make the mixer owner decide to leave and stop providing the service
The lagest Bitcoin mixer is about to stop working.
The question is, will the atomic wallet users get their money back because just a portion of that fund is traced to a mixer what about those that have been filtered into various other coins and currencies, I guest there is no form of insurance to cover this and is going to take a long time and process trying to get the mixed bitcoin back even if the mixers the hackers used is cracked down which is not something that can easily come by.
They have a large line in the terms of use that avoids the legal issue, so it is possible that one of the developers knew some backdoors and suddenly decided to collect the free money for his pocket. Here lies the danger of these closed-source wallets in the fact that you trust a developer who can withdraw your money and you cannot make any legally thing.
I don't like to say it but leaving your money in a CEX exchange may be better than using a closed source wallet.