
No, given the last few chapters, if he wasn't crippled, he could have easily avoided falling into this trap of being discovered by walking normally up to drink the alcohol. And in a previous chapter he mentions how he can pretend for a short while that he doesn't have a limp. The only reason he abandoned his initial plan of using rain to poison the sect by poisoning the roof tiles (which was why he worked on the roofs in the first place) was cos he had no choice but to reveal that he was crippled. The poison sect leader only accuses him of being the killer because he was limping as he walked up to drink the alcohol.
How did he become crippled? I don't recall at all