I'm trying to figure this out also. Using your example, so far my understanding is:
Find the verb in the sentence (ie. escape). This will give you one or more "templates" to check against (Verbnet refers to these as "syntax").
Now find all nouns/noun phrases within the sentence. If the sentence was "The convict escaped from London to New York". In this example we would have one noun phrase before the verb "the convict" and two noun phrases after the verb "London" and "New York" (or "from London" and "to New York" if you prefer. NP V NP NP. This would match to the syntax Theme V {+path} Destination where "the convict" is your theme (because it occurs before the verb, escape is your verb, "London" (or "from London" is your path and "New York" (or "to New York) is your destination.
If the sentence was "The convict escaped to New York" then your would use the syntax Theme V Destination (as there is no path). This is NP V NP. I'm still working on how to select the correct syntax but i guess I'll need to count the number of NP's after the verb to select the correct one although the use of "from" and "to" complicated things as in the example "He escaped from the heat". In this case "from the heat" i guess would be the path and there would be no destination.
Definitions for all terms (Agent, theme, destination) are in the manual you linked however these appear to be only for descriptive purposes. I can't see any way to determine a destination vs a non-destination (ie. He escaped the punishment).