How to Cache Globally Except for One Page
You could add a variable like globalCacheDisabled and {% cache globally using key 'entry_' ~ entry.id ~ '_elements' unless globalCacheDisabled %} and use a {% set globalCacheDisabled = entry.disableGlobalCache %} on the given page template.

On Craft's side I'd use a Lightswitch field on the entry with handle disableGlobalCache, which is disabled by default which you can then activate on the given entry/ies. 

This makes you prone to changing id's and differences across environments. (While testing make sure to purge the cache)