The movie, "A Most Wanted Man" -- how plausible is the ending?

We enjoyed seeing A Most Wanted Man, the last movie that Phillip Seymour Hoffman starred in. It's fairly well directed (director Anton Corbijn), with lots of detail piled up on the workings of German anti-terrorist intelligence spies. The story (a very complicated one), involves a Chechen-Russian guy who washes up in Hamburg, is somehow immediately latched onto by Intelligence, is taken up by a (naturally) beautiful young immigrant rights lawyer, and gets unwittingly involved in a scheme concocted by Hoffman and his spies to catch a Moslem professor terrorist-financier (or at least he's suspected to be a terrorist-financier by Hoffman's band). Hoffman is really good in a limited role. He's sort of a caricature of a hard-drinking, chain-smoking, hard-boiled disillusioned spy master.

Hamburg is filmed as a claustrophobic, bleak warren of tenement streets coated with graffiti, and with an occasional high-rise office tower looking down on the poor, hard-scrabble immigrants and their families.

Many spy films are something of a stretch, with the plots asking us to ignore some implausible connections. This one has its share. The Hoffman character uses the Chechen-Russian guy, Issa, as bait to catch the larger fish, the professor, even though they have no connection to each other. The professor is being spied on by his son, who ostensibly loves his father. And in the end, the Intelligence higher ups betray Hoffman's band and their schemes by nearly killing them all and arresting everybody in sight. I know that spies and their agencies have their rivalries and mistrust. Things go bad, as they do in all parts of life. But this ending strikes me as implausible. We're being asked to believe that German higher ups are willing to perhaps kill their own operatives and sabotage their  work on the streets of Hamburg simply in order to assert their authority. Perhaps it could happen. But if that's true, then we're all in even bigger trouble than I thought.

And what's with the cellphone Hoffman is using? In most scenes, it's a smallish Android type phone, but in one scene close to the end, the Apple logo reflects in the light, as if it were an iPhone. An obvious placement, and it looks like an out-of-context mistake by the film crew.