I have not seen this mentioned as a possibility , but what if that restaurant just had a concealed entrance to an underground tunnel complex leading to a distant bunker that has its own second exit? Whatever leaders entered the restaurant would just be laughing their asses off. It's definitely a possibility. That's why nobody's confirming anything until they see a body or DNA. But even if these murderous thugs did survive by the skin of their teeth, I can guarantee you none of them find that close call particularly amusing.
FWIW, there supposedly was some intel pinpointing their location within 4-6 meters. If correct, that would rule out your secondary bunker.
THE KNOWLEDGE THAT THEY WERE ALL STANDING WITHIN 4-6 METERS OF EACH OTHER WOULD COME FROM HEARING THEIR VOICES ON THE SAME LISTENING DEVICE. That is why there is so much confidence -- they listened until the *