The key to navigating back to specific tabs or to specific instances of fields is to give each of these specific things their own object name. That's the "Name" in the Position tab of the Inspector when that object is selected.
Once you do that you can use the script step Go To Object and give that particular name. You might go to a specific tab or to a specific field on a tab. If you go to the field, the tab that it is on will be brought forward automatically.
You might find it helpful in your scripting to use functions like
GetLayoutObjectAttribute() if you are getting info about a specific object.
In particular you might find GetLayoutObjectAttribute("tab01name"; "isFrontTabPanel") useful for learning if the tab panel with the object name "tab01name" is the active one.
If you are using FileMaker 13, you may want to consider using a pop-over for the editing of data fields.
You can iether populate the pop-over with the native fields allowing them to be edited, or use globals, which you can populate then write them to the original fields. This gives you the opportunity to cancel any edit, even if you have clicked out of a field and commited the record.
You can also build in a modicum of security into the popover, if you use a script to activate the pop-over.