I think it's VERY UNLIKELY foreign matter would get in either way. Remember we are talking about the turbine, not the compressor. The compressor is another story, people get stuff sucked down in those all the time through their own negligence.
But getting something in the turbine doesn't seem like a natural occurrence; mistake or not. And certainly wouldn't hang around for 100+ miles before causing damage.
I'm more inclined to think that maybe a turbine blade got bent during shipping, or install. And that could/would cause a improper balance, and demise.
Ship the upgrade as a complete turbo (exhaust included, because the turbine housing is part of any turbo IMO), and remove the chance for turbine damage.