When Arnold realised that he would be caught if he didn't do anything, he knew he had to sacrifice something for something.
It's either he lets the guards capture him and take him back to the messengers who would deliver him to the Steel Empire, giving him a pure chance of a terrible death. Or... He agrees to join the Wanderers and at least gets to wander around the Reach before figuring out a way to escape.
For sure, there was already one more favourable condition, and that was to truly join the Wanderers.
"Okay, let me out! I will join you! I promise!"
Arnold shouted loudly enough to let them hear him, but at first, it felt like they had abandoned him so suddenly. Or perhaps they had already left.
'F*CK! Can't they just wait to see if I can change my mind? What a disgrace!'
Soon, the guards were already drawing near, reaching him, and Arnold was already about to lose it.
