Quick note, there is no way to "stumble" upon Mol unless you found the small hole before saving the young Tiefling and shrank into it.
Now the whole need to leave but do not get a chance too is messed up and should be fixed I agree. If you did not start exploring before hitting the exit then you should be allowed to leave. As a Paladin I feel your decision choices are limited as well. Especially since you do not seem to get a chance to defend yourself from the accusations. There should be a persuasion option to defend your honor with the adults.
