Meditation Rooms in airports

Question

I had a business trip the other day. Praying at home or shul was not an option because it was before the z'man. When i got to the airport, i noticed a meditation / prayer room. It appears that any and all faiths use this room. There are no crosses, or other religious articles visible. (Except a cross behind a curtain that could be displayed during a catholic service. 1-Is it permitted to pray in a room as such? 2-Would it matter if there are other people in the room praying at the same time? 3-Does it matter if they are Muslim or Christian? Because from what i understand, we hold that Islam is monotheistic and Christianity is not really monotheistic. thanks for sharing your wisdom ds