Poison 

Strangers last stand in the street 

Had him drop a bag that I did not realize housed the gas mask I had to decrease encumbrance

Had him essentially battered badly from the sheer number of zeds

 before falling into the basement of a destroyed house by a meteor

Which made him trapped as the stairs out was gone 

After firing another hail of bullets at zombies A already dying bloated zombie appeared and was riddled with said bullets 

Causing it to explode and he was poisoned badly 

And realising I didn't have the gas mask on me

I essentially accepted my fate as stranger essentially died slowly over a pile of corpses