Ray was in the Ghostbusters headquarters, which was an old firehouse in NYC. He was the only one who bothered to come into work today. Egon was probably off collecting spores, moles and fungus, and Peter was probably trying to seduce Dana Barrett. Winston had come in for a couple hours but then left after he ate something funny.

Janine was at her desk and she calls up to Ray

Janine: Ray! Someone is here for you!