I have a different angle on this.
According to some science and research done on the destroyed city Tall el-Hammam (maybe Sodom Gomorrah) they found evidences such as structures on sand caused by extremely high pressure and products that were melted on the outside but was fine on the inside. The conclusion that came that could be the cause behind the immense heat was a exploding space rock.
The exploding spacerock was 1000 times more powerful than an atomic bomb. It exploded above the city which leveled buildings to the ground and setting fire on everything. After the explosion, the stones began to rain down on the city.
An exploding atomic bomb creates and immense light and UV rays. When the scientists back in the day was testing the atomic bomb they first needed to be in a safe distance and secondly wear certain type of glasses so their eyes don't get damaged.
Now imagine the eye-damage one would get when looking at an explosion that is 1000 times more powerful than the atomic bomb.
I think that the messenger Angels told Prophet Lut not to look back due to safety precautions.
Allah knows best ofcourse.