Hydrogel will become thicker at higher temperatures. The gel will stick to the hot burning surface and cool down the fire at the spot. This makes Hydrogel very effective, as the extinguishing agent is effective at the location it is needed most. It avoids spills and side damage of needing to apply an excess of extinguishing agent.
By its sticking ability, long term cooling is provided to hot solid surfaces, preventing it to catch fire again for a long time. This will provide the optimal option for a safe exit out of the fire exposed zone for the people present.