What should you do if you suspect a fire is still burning inside a door or window?

When a fire is suspected to be still burning inside a door or window, the priority is to ensure that the fire is completely extinguished to prevent rekindling or spread. Removing facings allows firefighters to access hidden spaces where the fire may be smoldering, ensuring comprehensive extinguishment. This action helps in identifying and extinguishing hidden pockets of fire that might not be immediately visible, thus reducing the risk of an unexpected flare-up.

While the other choices might seem viable in certain situations, they do not directly address the critical objective of ensuring complete extinguishment. For instance, leaving the area might be necessary for safety in some scenarios; however, it would not resolve the fire hazard. Similarly, checking for heat with your hand can be dangerous and does not guarantee that all hotspots will be identified. Calling for additional resources can be helpful but should typically follow the immediate actions that can be taken to ensure safety and extinguish the fire. Therefore, removing facings is the most effective and proactive approach in this specific scenario.