Rosalia is not really convinced by her comrades and thinks its pure folly to rest. In addition to the Evil presence being "somewhere near", some of her friends may end up as the kobolds and turn against her at night. Nevertheless, everyone looks quite tired and wanting a rest.
So she takes the first watch reassured by the paladin presence. Once it's her turn to sleep, she'll place herself as close as possible to the entry of the room and as remote from her potentially-deadly-contagious comrades!
Roderic stays as alert as possible during their shift, trusting more in Rosalia's keen senses than on his own. Once the shift is over, he wakes Grok quietly and removes his hauberk. He does keep sword and shield close to hand as he dozes off.
It seems as though everyone had just settled in for a much needed rest, when Roderic just catches a faint sound. It sounds a little like a stiff-bristled brush being pushed along the floor, and it is outside, near the last battle.
Peering around the cover provided by the resting area, Roderic makes out four giant rock centipedes similar to the ones they fought before. They haven't noticed him yet and they appear to be scavenging the remains of kobolds that were killed earlier. The odd sound is made by their hundreds of legs moving over the stone of the cavern floor.