We have a winner! Yes, it's Rainbow Six Vegas, but 2 to be precise, as you are a character called Bishop in 2. The hint was going to be 'Rainbows!' by the way. I've only just started Vegas 1, I got it on games with gold ages ago but only played it once, after Vegas 2 I thought it'd be a good idea to give the first one a go. It's really good, and I even prefer some of its features to Vegas 2.