I was in a four-way inter game yesterday, where two worms were skunked. Around the time sd was supposed to start, the worms stopped losing their 5 hp! A couple of turns later, these two worms were the only ones left for sd and their healths went down to zero as usual.
Why did the poison stop having its effect? I'm thinking it must be to do with sd, but I've never seen this before and I can't find anything online about it.