Valid reason for breaking one's oath

Q: I am a 15 year old boy.

1. Once I was playing an indoor game with my family and lost. In anger I sweared upon Allah that I will never play this game. Now can I play the game? Is there any expiation?

2. Similarly I once went to a relatives house where I had an argument. I then sweared upon Allah and Holy Quran that I will not go to that relatives house.

Please guide me regarding both the cases. 

Performing salaah with jamaat at work

Q: I work in a hospital. The nearest Musjid/Musallah is about 5-6 km away. Alhamdulillah we have permission to travel for Zuhr salaah during our lunch break (Our lunch break is 30 min, but it takes about 40min to go for Zuhr salaah and come back to work) and have been doing so for approximately the last 3 years.

However there are colleagues from other departments in the hospital who are not always able to join us for salaah. Should we request hospital management to give us a room to perform salaah with jamaat, and encourage other colleagues to join us for jamaat, or should we continue to encourage them to join us for salaah at the musjid?