He had no choice and no ammo, he couldn't use field repairs with 99 ammo or he would not be able to use mark target or AT nades, game was over when the insta gib rocket truck hit the field, that thing will kill everything unless you can kill the whole Axis army to get close to it. when you think how many T34-85's its gonna take to kill a Panther he would have needed 10.000 manpower and 6000 fuel..lol.
Ram was the only and pretty hopeless option.
I believe T34-85 + ZiS combo is enough to take Panthers, while ZiS with long range and shorter reload than T34 can easily penetrate panthers, T34-85 will be good as a support to ZiS and to protect flanks