Tomb Raider III Remastered Crushin' Krishna Kill Tony with Grenade Launcher

Tomb Raider III Remastered Crushin' Krishna trophy/achievement.
Defeat Tony using grenade launcher (on New Game)
You have to do this during your regular playthrough (not in New Game+).
The trophy is obtained at the end of the level "Caves of Kaliya", which is the fourth and last in the India section. You can collect the grenade launcher on the platform on the far side, as shown in the video.
If you did not collect the grenades in the levels "Jungle" and "Temple Ruins", you should pick up the grenades on the right platform. You need to have three.
I was unable to hit Tony with grenades from any of the other platforms, that why I jump onto his platform in the centre.
You can also do it without catching fire, but as you can see in this video it even works if you die.