Mia looked at Lucas from the corner of her eye. She could see his twisted expression as he glared at the Golem, but she didn't care. As for how she knew that Lucas was the one who had saved Selena and her team, it was very easy after she saw the group's condition and didn't need anyone to tell her first.
Of everyone she knew, Lucas was the only one powerful enough and had the fire element that could put Selena and the others in such a state even though it wasn't a direct attack.
While Selena was the only one with noticeable change, as her skin had been scorched, the others weren't completely clean either, as a few of them had signs of having suffered from intense heat.
After knowing that Lucas was the culprit, it wasn't difficult to tell what his aim for doing it was. Saving the group was only for his plan which was why he didn't particularly care about their safety and had ended up affecting them with his flames.