He probably should have known better than to visit the Middle East. There were certain, inevitable things he was going to see there and he really probably should have known better. But when he followed the political assassination track, this was where it brought him. He didn't choose it, and he couldn't walk away from it just because it was difficult. If this was where a major operation was basing itself, then this was where he had to be.
It's just that almost everywhere he goes, he can make himself understood; he is usually surrounded by British military personnel.
What is difficult is that he's learning about them. He's getting to know a little of what their lives are like. And their lives, make no mistake, are hard. They are dusty and sunburnt and hated wherever they go. They are never safe, and have stopped even thinking about it. Those sorts of thoughts would kill you. Holmes knows that very well indeed. They have learned hard to depend on nothing; they band together to have something to rely on, and to keep from being lonely. Their attachments, yes, are easy, but their loyalty is not.
Holmes wishes they would all just go home. It's alright. They do too. But no kind of soldier gets to choose where they go to bleed.