Well, at first Requiem is a dream, you are playing on the mind of Philips to find the exit, if you remember the BP, at the end when he send the message kill them all, he got knocked down by an infected disappointed of his behavior OR the hallucination/dreams of the virus took him back.
As far as BP tell us this, after the virus has been removed, the hallucinations and some issue remain.
So back to why explosive ketchup bottles ? then because during the adventure of Philips, he been terrorized by many events, in part, these old abandoned bottle of ketchup, breaking on the floor when moving them. On his dream (Requiem) his imagination make him think they are explosive.
And another part of the virus found in BP, during the realm part, we know that the person infected have to escape his dreams and solves them, that what Requiem is all about.
Requiem is a dream, don't try to understand why