At the time of the fire, Sasson, a religious education instructor was at a Shabbaton, an educational retreat.
We have previously discussed the curious practices used to circumvent the limitations by the Ultra Orthodox including elevators that require all riders to stop on every floor to avoid the need to push a button. Other practices are more serious including dangerous practices associated with circumcision. In this case, a prohibition on fire does not apparently prevent the use of electrical heat but only if you do not actually turn on the device during the Sabbath.
The deaths have caused ultra orthodox families to discuss this practice which is widespread in the community.