Hurdle
"They are fine," Erin said. "Look."
Liza saw the hologram of the map from Erin's watch. It still has the complete blue dots from the location of Fernando and his group. If you are wondering, what if the owner of the watch got killed and the watch was the only remained, that's why there is still a blue dot? It was simple. Nothing of that sort will happen. The watch monitored the heartbeats of its owner and it is the only one that those watches recognize.
Even if the watch got separated from the owner, it would still detect them approximately forty kilometers at most. And once the owner's heart stopped beating, the blue dots will be replaced by violet ones. That is now for detecting the corpse of the owner. This is also why Erin and the others delighted when they saw that for Amara and Sirius watch, it was still blue dots. Meaning, both of them are still alive.