Varian didn't expect this day to arrive. Especially after learning bits of Isadora's past, he thought it'd be impossible for someone like her to do something as intimate as Synergy.
They were just holding hands now. Nothing more, nothing less. But Synergy was a process that'd touch the soul.
Isadora agreed despite that.
Perhaps there were two reasons for this.
Firstly, without doing this, they had no chance of coming out alive. They'd be dead.
Secondly, and this was largely an assumption from his side. Whether she admitted it or not, Isadora hoped to have normal relationships.
She wanted to let go of that bitterness in her.
The fact that she's actively interacting with them, growing her bond with Sia and Enigma, not acting hostile with Varian and Sarah despite their frictions…perhaps all this was the manifestation of that inner desire.
But with her traumatic experience, she couldn't overcome it herself.