This was played on the PS4 Pro and I believe this could be applied to other platforms as well.

• Pick up the grenade
• Throw it at the parasite zombies
• Run past the first gamma while staying close to the left side
• After getting stunned by the second gamma, run straight to it's left and hit dodge using the 1 2 method (As said by many many others before, this takes practice)
• Pick up battery pack
• For the upcoming third gamma, use dodge to get closer to the hole and DODGE AGAIN far away from it
• For the fourth gamma, run straight to it's right and hit dodge using the 1 2 method (As said by many many others before, this takes practice)
• Right before the last gamma jumps out, aim your weapon to avoid the stun
• Dash quickly to the safety lock door
• Dash precisely to the battery pack
• Turn around and as soon as you exit the door, SPAM DODGE AND HAUL ASS

Enjoy.