The "limited skill assign" aspect of the idea may be difficult/messy to represent visually if there is already a number above the lem's head (but not impossible).
Also, having slept on it, I'd prefer the lem to explode rather than become a neutral. Reasoning: it acts like a finite game timer for just 1 lem, which is an interesting concept, plus the fact that it leaves a crater means it's potentially useful as a destructive lem, which could form part of the solution. Finally, 'countdown timer above head' is synonymous with exploding in Lemmings, although this is a weaker reason; new behaviour (i.e. becoming a neutral rather than exploding) is easy to learn.