Ok here is the deal with the original question but before that here the concept of the cargo fire suppression
Once a fire smoke is detected inlet and outlet isolation valves close (so no air gets in and out) . With the discharging of the agent ( halon ) oxygen is “inactive” so to speak . But the assumption could be that the fire started from materials producing thermal runaway , so at some point fire could start propagating again .
I was in simulator sessions in which the suggestion was to have a cabin crew member place his/her hand on the floor at several intervals over the affected area to see if it feels warmer thus indicating deterioration after the initial discharge . Initially I didn’t think this through much , I just used it in subsequent sims . Then upon landing , if we did not have indications that fire is active , we would proceed to the parking stand escorted by the fire department , instead of emergency evacuation .
Now since there was the thought of utilizing a crew member touching the floor to establish whether or not it feels warmer ( as a basis for consider among else emergency evacuation ) , would it have been more objective to use the temperature indication as alternative means of determining fire propagation? A hand placed over a carpet which in turn is over a few layers of metal , if it feels warmer than usual it probably means that fire is really spreading around . The better indicator to this is seeing i.e an intitial 20 degree indication at some point being +40 and rising in a sealed cargo hold .
There are a different operators out there that do use the hand logic . I just hope we didn’t trap our selves into a singular technique as opposed to a better (yet not much thought of ) alternative .