By "there would be a relief", I presume you mean "they would have created a relief sculpture", rather than "they would have felt emotional relief". As written

By "there would be a relief", I presume you mean "they would have created a relief sculpture", rather than "they would have felt emotional relief". As written the sentence is ambiguous, and right at the point where you pivot from evidence supporting the slave escape narrative to evidence contradicting the slave escape narrative, so I can't be certain my reading is correct despite it fitting much better with the following sentence.