When Bert (Lance Reddick) is talking about their "creator", who is the original Albert Wesker, he mentions that "He died in a volcano."
This is a direct reference to the events that took place in Resident Evil 5 (2009). In the main continuity of the Resident Evil universe, Albert Wesker, who was the main antagonist in some of the Resident Evil games, was killed by Chris Redfield and Sheva Alomar during their final stand-off inside of an active volcano.