The VWP grants admission for upto 90 days to "contiguous territory" which is defined as the United States, Canada, Mexico and "adjacent islands"*.

As per this rule, travel within "contiguous territory" does not relinquish the status conferred at the initial POE and hence a person may be found to be "out of status" (and hence subject to removal and disbarment) even though they may not have violated their terms of admission by virtue of physical presence in the United States.

(* - "adjacent islands" in turn is defined as "Anguilla, Antigua, Aruba, Bahamas, Barbados, Barbuda, Bermuda, Bonaire, British Virgin Islands, Cayman Islands, Cuba, Curacao, Dominica, Dominican Republic, Grenada, Guadeloupe, Haiti, Jamaica, Marie-Galante, Martinique, Miquelon, Montserrat, Saba, Saint-Barthelemy, Saint Christopher, Saint Eustatius, Saint Kitts-Nevis, Saint Lucia, Saint Maarten, Saint Martin, Saint Pierre, Saint Vincent, Grenadines, Trinidad, Tobago, Turks and Caicos Islands and Other British, French and Netherlands territory or possessions bordering on the Caribbean Sea")

In brief, the person would have to travel at least as far as Guatemala in order to qualify to "reset" the VWP clock.