Combine that with the teases fans have already gotten about potentially radiated walkers in Season 5, and it certainly throws an interesting wrinkle into the narratives of both shows.
The easier-to-understand angle is that the soldier-esque people Al engaged are indeed part of the same group that Jadis was in contact with on The Walking Dead.
Fans have already suspected that the ringed symbol looks enough like the traditional biohazard symbol that it probably indicates radioactivity in the area.