There is a perpetrator and then a victim. Both meet because of similar vibrations. You are the creator of your own experience. Definitely your reaction upon the event is within your control and largely depends upon your perspective. But even the event itself could have been the creation of the parties involved - maybe not always conciously - although with some introspection and analysis of past thought, it does sometimes become clear that you brought it onto yourself through your thinking.
Finding happiness does not come from understanding what makes someone else tick - it comes from understanding yourself and Life.
Firstly, I would have called him back in exactly 64 seconds. Secondly, I would have scheduled a meeting with him. I would have asked him if everything was ok because he sounded really stressed over the phone. If he is compliant to answering this, I would have written down a list with him to see what and where things were going wrong. I would have left him with the list and made a second meeting. This would give me and him time to see what could be done about the problems he is facing and try and rectify them. Perhaps it may be that other people in the office don't realise what the problems are and a meeting with the relevant people who could help solve the problems could be called.
I do not believe that people who are coping react like this and sometimes need help. Whether it is an entirely different department or not, a business is a team and if one person is overwhelmed or not coping - thereby acting out his frustration on others, it is up to the whole business to help. A business is a team. If one person if failing, then the whole team is not being as productive and successful as they could be.