skedaddler

I just started playing, and while this specific situation doesn't matter much, I do want to understand how the mechanic works. I have a pioneer that has been attacked by a spider that far outclasses it. I have run to the glowing tiles on the edge of the combat board, but it will not allow me to move onto them. Am I wrong that these are the "escape tiles?" Why am I unable to escape with my pioneer? are there conditions for escape? I've done my best to search this topic on the forum, bu