Mercy spent her 'rest time' by wandering around the cave with earphones in, not being able to sit down in one place for longer than five minutes. Occasionally she scribbled something on a wall with a laser cutter, be it some pointless doodles or actually nice drawings - At least as far as one can get creative, doing some shallow carvings in the wall. The girl didn't want to disturb the others, but at the same time she simply didn't have enough self-discipline to just sit there idly and wait, having no real need for rest.
When Horace made his appearance, at first Mercy was confused, even pointing a gun at him there for a moment. However, after asking dozens of questions, and the whole situation clearing up, she pretty much glomped the guy, happy that, well...One less person is dead.
"Well...We sure ain't gonna achieve anything if we stay here for any longer..." Once they came back from outside, few minutes later the girl showed up with her backpack at cave's exit, seemingly ready to go. "...Eventually one of these things will stumble upon this place. Izzy's right, we should keep moving." She looked towards the exit, squinting slightly at the light, then turned back to the group. "...Also...I thought we could make a better use of these while we travel..." Mercy pointed at the bracelet they all used to communicate. " What if we send out a scout that will march some distance in front of the rest of the group? I mean...He'd be harder to spot, and we get a heads up if something happens...It will also limit casualties if...you know..." Her smile faded for a moment. "Anyway...just an idea, I think some bandits and caravans do something like that back on Earth..."