As far as I know, this area where the blast pit takes place was an area of Black Mesa that manufactured missiles in the epoch of the cold war but when the cold war ended this part became an area for dumping toxic residues from Black Mesa, that explains why have so much toxic waste
IIRC it’s meant to be the older style medkit of the facility, as this area is ‘old Black Mesa’, at least in BM
As far as I know, this area where the blast pit takes place was an area of Black Mesa that manufactured missiles in the epoch of the cold war but when the cold war ended this part became an area for dumping toxic residues from Black Mesa, that explains why have so much toxic waste