On the beam…
The crazed screaming of the gold-witch — no burbling now from that hideous creature! — increased behind him as he cleared the doorway, a bare half-second before the heavy door slammed down. Bernice was already yanking on the large switch mounted by the door, hard enough for it to creak as the circuit slammed closed. That part of Greg still capable of reasoning thought approved; the switch was built to take it at least once, and it was for damned sure that nobody would be using that room for anything, any time soon!
The rest of him instinctively concentrated on shying away from the reinforced window looking into the room. The blast shutters had snapped shut, and they should have been as immobile as tungsten steel over composite armor could make them; only they were now faintly clattering from the titanic forces now contained in the room. He could feel the first tendrils leaking through, lashing at local time-space in ways that could not be described, save as corruption in the nose and a roiling in the gut. Time itself stuttered, in slow, sickness-inducing waves, stretching the current moment like taffy in the sun.
The three seconds between the blast door’s closing and the first wild electrical surges felt like a grotesque, nigh-eternal Now — but it was, indeed, still ‘only’ three seconds. Greg could feel the intrusive, blindly questing fingers of corruption suddenly shudder and sublime as the gold-witch was electrocuted, its calls (faint, but damnably perceivable!) devolving into a shriek of mortal pain before being abruptly cut off. Greg thought he could feel the surge of regular reality pass through him as it rushed to fill the newly-made vacuum in space-time, and the sheer relief of it staggered him as he stood.