All planes are tested and certified to evacuate a full load of pax in 90 seconds using only half of the cabin doors.
So it could have been done easy on the LHS only.
I am repeating this, CC are very well trained to evaluate the outside conditions and respond to commands. They were already in state of alert. A command to evacuate on the LHS would have been perfectly understood as they were all aware of the RHS fire.
Stop discrediting cabin crew's abilities, decision making and training. Unless you know very well what a cabin crew training is like in a major airline you would better refrain.....