If by special you mean the distortion drive, it gives a few invulnerability frames, so yes... if they give you a bit of breathing space during a blockstring like that, you can throw it out and pass through the next attack.
Also, the problem is that you said you used a special while he was "comboing" into 5D - meaning he must have already been hitting you. If you're blocking, the proper term for what he's doing is a blockstring or just a string.