You can absolutely still save in 1v4 with a flashbang from a locker pull, it's all about the timing. You can't with a flashlight. However I will say in 2v8 you can still flashlight save from a locker, I did this previously (as attached in the video). But you're not going to be able to stop flashbang saves at a locker unless they disable it completely. As long as you know the timing, you can get the save.

Honestly you're going to see this a lot when 2v8 comes back. I've seen a lot of content creators specifically making locker saves happen all match. Best way to counter is to ignore the survivor jumping in the locker and look around for the nearby saver. If theyre both going in a locker than just ignore them completely. Unless they really do add some type of immunity to blinds with lockers.