How could Tessio not have known?

We are supposed to believe The Great Massacre of 1955 took place on a single day. We see Willie Cicci murder Carmine Cuneo in the revolving door of a hotel. But later on when Tessio arrives at the Mall to meet up with Michael for the meeting with Barzini on Tessio's turf in Brooklyn -- where Michael would be killed -- he is stopped by Corleone button men, among them Willie Cicci. Cicci, who first killed Cuneo earlier that day, is now wearing a different suit and it's therefore reasonable to assume many hours have passed.

The question is: how could Tessio not already have been informed about all the killings that took place? Did news travel that slow in New York in the mid 1950s?

I believe that the Great Massacre scene was contrived to provide maximum visual impact--and logic be damned. How could Tess not know? Sure. How did Cicci and Clemenza get back to the Mall in Long Beach, Long Island, so quickly after whacking their targets in NYC? How did fat Clemenza survive after climbing all those stairs to blow away Stracci in an elevator car--and how did he know which floor to stop on? It goes on and on...but it was a great scene.

Ain't that the truth.

It is definitely a great scene, taken aside its flaws.

It is believed that Stracci had a meeting with people on that floor. Clemenza ovb came an hour or 15 minutes before..

I think, they were murdered in this order:

- Tessio
- Barzini
- Stracci
- Cuneo
- Tattaglia
- Carlo
- Greene

While the others are disputable, Tessio must have been the first one.
In the novel we read:

We read this part after the the chapter about the killing of Barzini and Tattaglia, but it's the typical Puzo style of revealing later what happened before. (Just like Brasi's death)
In Barzini's office, they would have known of Barzini's death if it happened even a few minutes before.

I think Moe Greene wasn't killed on the same day, but probably earlier on. In the novel he was killed months earlier in the home of his girlfriend in Beverley Hills.

When talking to Carlo, Michael told him Moe Green was dead, so it's safe to say Carlo was last...