Frederick Douglass' escape from slavery in 1838 was a carefully planned and risky endeavor, and his success was due to a combination of factors. While it is impossible to say with certainty what would have happened if Douglass had attempted to escape while still working in the fields, there are several factors that suggest it would have been more difficult for him to do so.
Firstly, working in the fields would have made it harder for Douglass to acquire knowledge and skills that would be useful in planning an escape. Secondly, Douglass' location in Baltimore provided him with access to a network of abolitionists who were willing to help him. Thirdly, Douglass had already established some connections and gained some knowledge of the city of Baltimore, which helped him plan his escape route.
Lastly, Douglass was able to pass as a free black sailor, which would have been harder to do if he were still working in the fields. Overall, it seems unlikely that Douglass would have been able to escape if he were still working in the fields, given the challenges he would have faced in terms of knowledge, connections, and the ability to pass as a free person.