The scene :

The military police marching in the hospital towards ROTH's room. The NURSE runs and opens the door and screams. An officer walks into the door to see MICHAEL's BODYGUARD holding a pillow over ROTH's head. He fires five shots, killing MICHAEL's BODYGUARD

The question :

- Why is the M.Police marching towards Roth's room?
what business they got there?
-They seem to be in a hurry like they know Michael's bodyguard is going to kill Roth...if thats the case,how do they know?

-and who sent them to save Roth?(if there was someone behind it...)

I always assumed that the Cuban police were contracted by Roth or Ola or someone to protect Roth while he was in Cuba. Because of the official function that night with the New Year party and the President being there and everything, the police didnt stay with Roth. Then, they somehow recieved a tip that someone was gonna try to kill Roth (this is where it gets a bit shaky), marched up to the room as quick as they could, and shot Buscetta (the bodyguard) in the room.

As far as who tipped off the cops or how much they knew, I'm not absolutely sure. Although just pondering over it, makes me think maybe it was Fredo. What if, after Mike tells him in the cafe (banana daquiri scene) that Hyman Roth "won't see the new year," he runs to Ola or the cops, tells them about Mike's plans, and then the cops run up the room, catch Buscetta in the act, giving them an easy excuse to kill him, and BAM, its over.

Interesting theory, good question too.

^^^^

Another extension to this point is that during the new years eve party, we see fredo leaving and micheal asks where are you going? Fredo replies by sayin he needs to get himself a 'real' drink. I always see this scene as where fredo may have warned the authorities about roth's imminent assasination.

Roth was Batista's buddy. The MPs were sent there as a gesture by Batista to protect Roth while he was spirited out of Cuba if necessary since Castro's army was closing in on Havana.

I think there are three possibilities:
1. Fredo tipped a contact in the Cuban government when he said at the party, "I'm gonna get me a real drink..." Recall that Fredo'd been to Cuba before--at the Superman show, when he made his fatal slip-up, he said, "Johnny Ola took me here."
2. Mrs. Roth tipped the military, after returning to her and Roth's hotel room and finding Johnny Ola dead.
3. We can assume that, since Roth had arranged for Michael to be driven from the party in a military car "for his protection," someone high up in the military (or his pal Batista himself) was in on the plot to kill Michael. When Roth failed to show at the party and wound up in the hospital instead, that high-ranking person put two and two together (those military guys looked to be in a big hurry to get to Roth's hospital room).

I strongly feel that scenerio number 3 above, written by Turnbull, is the most probable reason that the Military went to Roth's room.
I have read that in real life, when Batista was overthrown by Castro and the rebels, the Military, under Fidel, marched through government buildings, public places and hospitals to take over everything and to make sure that there were no more Batista supporters left, so the Fidel Military basically went through every conceivable place to search out and take over.
But as far as the movie goes, Turnbull's scenerio is the most logical in answering the question of how the Military was so precise in walking directly to Roth's room.

Don Cardi

Although it must be mentioned as an option, I highly doubt Fredo alerted anyone of anything(though the real drink part will be forever misteriously suspicious) only because 1)If he was going to, he probably would have after Mike talked to him in the daquari scene and 2) Fredo wanted nothing to do with Roth and Ola because "you guys got me in deep enough already"

I never really liked the fact that Fredo was a traitor, although I did always believe that it was true. However, with scenes like this, you have to wonder if Fredo was such a nice guy. Yeah, he was dumb, but then again you would have to be to try and conspire against your own brother, the Don of the Corleone Family. I'm sure he didn't like the fact that he was out to kill him, but I think that he just wanted to do whatever he could to gain respect, and it's not like Michael was ever Fredo's buddy anyway.
But, you could also say that in informing the government of Roth's assasination plans, it could be his innocense, his dumb wit, leading him to keep Roth alive. Maybe he thought that he would be a hero, or maybe he wanted to see his brother dead.
Either way, Fredo was a traitor, and you can't forget that. He assisted in trying to kill his brother (whether he understood the hit or not), why wouldn't he try and screw up Michael's plans to kill Roth?

I've always thought that they probably found Johnny Ola's body and knew that whoever killed him was after Roth as well.