Most comments have ignored the fifty percent chance that the burning train would be on the northbound, station and exit side, Platform 2. The normally very few people waiting on Platform 1 would move away from the fire and could easily move toward and be accommodated in the refuge.
In the scenario that a fully laden train would be afire on the 'island' Platform 1, the vast majority of the panicking, exiting passengers who would not see any signs and people would flee either north or south along the platform 1.
There is no safe area or exit to the South from platform 1 with a very high chance that in an emergency people would flee onto the MML(bind bend+ abutment), Hope Valley(bind bend+ abutment) or attempt escape by scaling the embankments. A contained area might encourage people to feel safer and stay put.
If people in panic were fleeing northward and got past the platform end fence they would be in a much, much bigger, flatter expanse of ballast area between the converging lines and in panic would have a much better view of approaching rail traffic if they foolishly decided to cross the HV or MML lines