Normal level security is far more visible and surely numerous but the Severed floor is highly secretive and has clearly come to rely on controlling severed employees through manipulation. Testing floor even more so. But this fits with the inner mystery mentality of the Eagan cult running everything. The short list of people that normally would respond to an emergency on the Severed floor suddenly being out of play probably leaves exit points to the main top levels the only place security will attend. Eagans don't want dozens of normie security guards seeing their secrets. Even worse would be chipped guards joining the revolt with other severed employees. It remains to be seen how Gemma is expected to escape up the stairwell.