When Holmes, Watson and the Gypsies go to the arms factory, Holmes leaves Watson a note asking him to meet him at the big tower. Holmes gets captured by Moriarty and his henchmen. Watson runs into some trouble with the sniper guy and blows up the tower, dropping it on the structure where Moriarty is holding Holmes captive.
Some of that was planned, we find out in the end. Holmes needed to get very close to Moriarty in order to swipe his little red notebook and replace it with a fake one. But Holmes sounded genuinely surprised and annoyed when, during the aftermath of the altercation, he says to Watson something like "you didn't so much find me as drop a tower on me!". But, if he had meant simply for Watson to rescue him from Moriarty, he wouldn't have directed Watson toward the tower and instead would have summoned him to the torture chamber.
Or did Holmes mean for Watson to run into trouble with the sniper and blow up the building with the mortar the whole time?
What was intentional and what was not part of the plan during the conflict at the arms factory?