Assuming a round to be equal to 6 seconds of real time (the Dungeons and Dragons assumption), that's about 408 years of paralysis which will probably hinder one's adventuring career.
An interesting question, though I'd point out that the squares seem to be roughly character-height in size, and DnD characters walk noticeably faster than that
It ended this particular adventurer's career, along with his life. That still took some time since his defense value was rather high and warlocks didn't have a ranged shot on him since he was already swarmed.