The company that makes those locks has two different styles, one is made from cast zinc and is prone to breaking, the other is steel, much sturdier. Even if you have to pay for the replacement yourself get the steel model!
Hope you got the emergency window back in, normally it falls out and breaks when you open it. If your window didn't break it's normally a real PIA to put back in, but you've probably already figured that out by now.
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