Can any attacks knock an enemy out of a Zarya ult?

Certain enemies caught in a Zarya Graviton Surge can escape as answered in Which heroes can escape Zarya's ult? but can you or your allies accidentally knock an enemy out of the surge once they have been sucked in?

For example if a Winston in Primal Rage starts swinging at enemies caught in the ult will they get knocked out?

Can you knock enemies out of an allied Zarya's ult?

Yes.

Abilities and attacks that can take enemies out of an allied Zarya's ult include things like Roadhog's hook, Reinhardt Charge. However, not all attacks can knock enemies out. Pharah's Concussive Blast, although strong enough on its own to knock players far away, does little to nothing in a Graviton Surge as it will pull the player right back before they can escape the ult. Same goes for Winston's ultimate -- despite how strong it is, playing as Winston I have never been able to knock enemies out of an ult -- as it will only deal damage.