wondering why they didn't go to ''firewall '' power.
JNB is hot and high. They were very close to MAX ToW and there would have been little or no extra left.
and extend more flaps, I know that is what I would do on my type.
Then they would have had "Land" Flap with no extra lift and a bucket full of drag, and then they definitely would have died.
The 744 takes off with Flap 20. Flap 25, one extra stage, is land flap.