I'd leave it as it's now, since it can kill something so you need to take some time to place them. There should be a maximum to kill of like 2 models, since it can wipe all units when you pop them out of the building, which is just plain stupid.
I think, that flare mines should not deal damage at all. It might be unrealistic, but if that mine can kill even few models, what for then USSR needs doctrinal anti-infantry PMD mines? They suppoused to do same - deal small damage to enemy infantry, they are cheap also.