With Ra's gaze fixed on Lex, a pressure fell on the room and everything became still. This pressure was not like that of divine aura or Dragons Might, which Lex could overcome through sheer force of will and determination.
The entire room froze still under its effect, including Fenrir and the hands as well. The only thing still working was Lex's mind - he could not even drive his energy at the moment. Lex did not panic, but he was cognizant of the fact that he was stuck in a tricky situation.
If Ra were so powerful, he could instantly freeze them all to begin with, and then there would have been no reason to put up with their previous farce. But he hadn't and even tolerated the humiliation of being attacked by Lex and Fenrir at the same time. He even suffered many wounds from Fenrir, though for some reason he attributed the hatred from that to Lex as well. The point was, Ra's ego would not allow him to tolerate such a thing unless it was absolutely necessary.