First thing I notice (it could just as well be a typo in your post) is that you use <b>key=</b> in the cache block statement, but the documentation says it's <b>keys=</b>.
If the typo is only in your post, what is the value of $get1 to $get4? Do those variables contain the name of the GET variable or do they contain the value of the GET variable?
personnaly I would drop the idea of using that line altogether: {set-block scope=root variable=cache_ttl}0{/set-block}
This will simply remove the cache on your page, and will really require far too much processing power on your servers. and then re-include the cache manually, for a set of area.
You would be better off, converting your parameters into view_parameters if you can: http://ez.no/doc/ez_publish/technical_manual/3_10/templates/basic_template_tasks
Or create a module view extension to collect the information from your form. That way you can collect the information in the script of the page, and cache the result page. http://ez.no/fr/ezpublish/documentation/development/extensions/building_an_ez_publish_module
If you really want to use cache blocks, you would be better of using it the other way round. use a cache-block to unset the cache for one area, not for the entire page and then ressetting it for every part.
