the person here wanted to shut the door (stop contact/disengage) against war. Buy in doing so, he/she also lost contact with the rest of the world. this was unexpected, but rather fortunate/lucky for the concerned person. "fortuitous" means the same. unplanned/luck by chance. for example : a person in a humid climate, wanted a gentle breeze, but suddenly it started raining. so, it was a "fortuitous turn of events" for that person. he/she got more than what he/she wanted in the first place. it was unexpected but fortunate.