As rmg alludes to, the behavior will depend on the structure of your service.
The exit step will exit the nearest ancestor flow step where the Exit from value matches the label value of the step. If an empty string is used in the label, the nearest ancestor step without a label will be the block that is exited.
Refer to the Developer User’s Guide, Chapter 7, “The EXIT Step” for details. Then try out some tests on your own.
My advice is to always explicitly set the Exit from and not leave it blank. This will avoid confusion and possibly unexpected behavior.
#Flow-and-Java-services#Integration-Server-and-ESB#webMethods