TMNT Mutants in Manhattan: Unreachable collectibles?

I'm playing Teenage Mutant Ninja Turtles: Mutants in Manhattan for the Playstation 3. Of course, with the game being somewhat heavy on goodies to grab, I try to nab as many as I can get my hands on.

However, something has come up situation-wise with these gray crystals: the ones I haven't collected are inside buildings which by all means seem to be impenetrable. I can see the crystal through some grates in the roof, but even looking at the inside of the buildings through the grating shows no possible means of entry. 

Usually these crystals would be behind large garage-like doors, but the buildings I'm looking through have no indication of doors on the outside or even have no doors due to being surrounded by other buildings. 

All attempts to destroy the roofing fall flat as well, even grabbing extremely valuable items to try and blow it up result in zilch. Did the game designers really leave unreachable items for a chuckle, or is there something I'm just not seeing?