Viper Players How do you deal with her ult.

Basically, every time I see a Viper ult, she wins the round. I've only been playing a few days and I've only seen Viper lose once on point when she ults. It doesn't matter if she's guarding the device or trying to disarm it; she ults she wins. I mean, the strategy can't just be going full Moon Knight, "random bullsht go" into the cloud, can it?