Guards can be extremely hard to deal with but they aren't really all that scary if you catch them off guard.
Certain types of cover and obstacles are good at negating PTRS fire, as the PTRS often hit those before reaching the infantry models.
If you have the munitions to spare, grenades can be used to help fight guards. Not for the damage but to force out the signature Guard dance. No use throwing grenades if you have nothing to follow up on it though.
While PTRS works against light vehicles your Flak HT should still be able to reliably fend off one or two guard squads attacking it. Not that useful for pushing the guards off though.
