So yeah, when they pinch-hit Ewing for Brujan, they could have (a) pinch-hit Baty instead, and had him slide in at third, pushing Bichette to short, or (b) pinch-hit Ewing (as they did, of course), and kept him in at center, sent Benge to right, MJ to first, Vientos to third (where he could have been pinch-hit for in the ninth by Baty), and Bichette to short.
Or they could have done all of that but pre-emptively inserted Baty at third in the top of the ninth.
The point being that Vientos did not have to face Iglesias in the ninth. Baty is slumping just as hard at this point, but at least you get the better matchup and better speed and defense.
I think they kind of hate the idea of M.J. in the infield, though, even for one desperate inning.