Is it permissible to break the fast in Ramadan due to a difficult foundational training course in firefighting abroad?

Participation in training courses is not a permissible excuse for breaking the fast in Ramadan (definition). The permissible excuses for breaking the fast are travel, illness, and similar conditions such as severe hunger and thirst that could lead to perishing.

The questioner and his companions must fast. If any of them experiences excessive hardship and fears harm to themselves, they are permitted to break the fast and make up for it after Ramadan, based on the Almighty's saying: "And do not kill yourselves. Indeed, Allah is to you ever Merciful," and His saying: "Allah does not burden a soul beyond its capacity," and His saying: "And He has not placed upon you in religion any difficulty."

However, if the questioner and his companions are traveling a distance that permits shortening prayers (83 km, starting from the last buildings of their city) and do not intend to reside in the country they traveled to for four days or more, then they are permitted to break the fast due to the excuse of travel.