While out trying to retrieve the stampeding horses, you come across a dying campfire. It doesn't belong to anyone in your group, and it was lit within the last day. Other survivors? The folks who staffed the laboratory here? Someone else entirely?
Comment below to discuss and vote on how to proceed. Track down the horses? Try to find the other humans? Split the group in order to do both? Or something else?
Cliffs and Caves Group:
The light on the radio tower begins blinking again. Did Sam manage to fix it, or did it come back on its own? The answer is unclear. The humming of the electronics makes you suspect that the tower is transmitting something, you just can't tell what.
While Petra is out fishing, she comes upon a small lifeboat. It looks pretty banged up, but is still floating. Markings seem to indicate it is a lifeboat from the ill-fated ship that brought you here. It looks like it could hold up to eight tightly packed people, four reasonably comfortable people, or one person and a horse.
Comment below to discuss and vote on how to proceed. Wait for someone to respond to the radio signal that might not be transmitting? Try to get the humans off the island with the hope of coming back for the horses? Send one person out in the boat for help?
If your vote isn't registered within two weeks, your character will be assumed to have gone with the majority opinion. You may either draw your group discussing the possibilities (before the vote is finalized) or the aftermath (after the vote is finalized). You may of course do both if you are feeling ambitious.
If your character has any points in leadership skills, their vote counts twice. Only humans get a vote, unless the horse happens to be a sentient ponycorn with opinions or otherwise able to reason and communicate its thoughts to the group.