It's hard to answer because you haven't given a context, plus what you have given is grammatically wrong. I'll try to interpret it for you. "Should that come" (not 'comes') = if that comes. This still makes almost no sense, unless you mean "should that come to be" = "if that happens". "I shall inform"... inform whom? You must always tell us who is informed. Basically, I guess your fragment means "if that happens, I'll tell someone".