I did this by accident in the end, but the way to do it is to make sure the time on your filter reaches 0 and then wait for Artyom to start suffocating whilst in backpack mode and in an hotspot for radiation.
Craft a new filter and then back out of the backpack. It should apply immediately on lower difficulties and unlcok. On Hardcore I'm told you actually have to press down on the D-pad, which takes up more time.and ends up with Artyom dying.