Thermal runaway is very dangerous. I once saw a cessna tweetybird trainer with half it's nose blown off from a runaway battery.
You should monitor the temp lights of the battery when in use(if equiped), and if a high temp is detected, shut power down from the battery, and if possible disconect the battery. Allow battery to cool. If battery is in a runaway condition, you may try to cool it with a co2 extinguisher, but be cautious, as it may explode if it is too hot.