I am shocked that people don't understand the difference between a special and a primary weapon. An ice breaker is not a primary. I witnessed one guy attempting to use ice breaker in vanguard tiger strikes as a primary. After 3 runs I decided I wasn't going to carry him and let him sit back. So I refused to move and forced him to move up to engage. He still refused to switch to his primary. I saw him die no less than 7 times because he would keep trying to engage enemies with an ice breaker at cqc range. I understand you wanna level it but really...do that on your own time. Use it when appropriate. Once he finally switched to his primary he stopped dying.
Maybe just that guy as I use it as a primary and solo'd a tiger strike without dying. Heck, one playlist and all 3 of us were using it. Takes skill, like a shotgun, gut it makes a hell of s statement.