Help with boss fight (Pupa)

I am finding this one difficult simply because I have cannot avoid the lightning strike. I usually go up the stairs to the balcony attack from there. When he charges me, I simply prone and he goes right over me and misses me. I have plenty of help packs and can dodge his regular bullet fire pretty well.

My weapons:
RPG2
Basic assault rifle
C4

Supply marker.

My strategy so far:
Use the RPG to hit the big red coil looking thing, take out my rifle to hit some of the lightning rods he throws out. Then use supply marker to resupply my RPG2 ammo.

His lightning attack seems to kill me half way through the battle. Any advice?

Any tips on how to handle his lightning attack? I shoot and destroy some of the lightning rods he throws everywhere, but it still annihilates me.

Take cover behind the corners where the ladders are located for those electricity attack, or near the exits that Pupa uses.

no matter what part of the area you go to, make SURE to destroy all of the lightning rods that land near you.
if you are staying near those alcoves, there should only be 1 or 2 that you HAVE to destroy.

like DC Sniper said, bring one of the Heavy Machine Guns. more ammo=less time reloading.

All i say is use both the assault rifle/machine gun and the RPG2 against the pupa and dont worry about lowering your heroism with the supply markers spam them put 3 down stay in that area and when you need ammo for both weapons call one and then repeat. if you can make the missile launcher the one that locks on to things it make the AI fight a hell of a lot easier.

camp in the places pupa goes into and this fight is easy

My Tactics are very similar to Ryan Lee above me.

I went with naked camo, Law, RPG2, Grenades(you never know), supply marker, rations, chips, curry, one item for psyche, and the analyzer(never used it).

My Strategy involves staying in the tunnel you start in front of, running back and forth from one end to the other. The Lightning mines never go that far and a good portion of the battle, the 2 walls on either side make awesome cover. Start by setting down a supple marker and blowing thru your ammo, i only had to resupply once. it took me 5:44 time to beat and i got an S rank.
Other people probably have gotten faster times, but i play very consciously.

how do you get the RPG2