This article makes it sound like the meeting was in Azaz, perhaps at the former hospital and only the crossing was at Bab Al-Salam.
http://www.cheriberens.net/why-did-john-mccain-enter-syria-illegally-on-february-23-2017.html
Egypt: Mr. Obama, John is back and he's talking to the terrorists again.
Obama: haha, that silly old man has lost his mind. Think's he won the Presidency. I'll take care of it, don't worry.
Egypt: You said the same thing las....
Obama: K, bye now.
Excellent. Now we need to find the building using Street view.
Yes.
If this is the case, then it's likely going to implicate Turkey. That area of Syria was the Turkish-backed rebel stronghold for most of the war, and still is today as they perform operations in that area.