It was at this moment, Sakura knew.
She fucked up.
Rena's Seki pushed her out of the way just in time, as two Bakudou were used to block most of the swords, a shield of ice blocking the last one, a Hado to counter the modified Byakurai, and then she just sat there and took the rest of the damage, staring directly into Sakura's eyes, her spiritual power flaring at its' peak, not moving an inch while she stood there.
When all of Sakura's attacks had failed, she felt her muscles calm down as Shunko ended. Her hand's lightning turned off, and she knew she was fucked.
Sakura had exactly three seconds to react. She spent one second going over her options; if she activated Soul Scale, she'd have to block the incoming attacks directly, though that wouldn't be too hard to do depending on their speed. If she activated Lightning Armor, Rena may hurt herself by attacking, but would that stop any of them? Wait, could she even use that one? It was a technique she had in Shikai... shit, she only had one option.
The second second was spent activating Soul Scale, channeling reiatsu through her arms and legs to cover them with a malleable armor roughly as strong as Zanpakutou steel. While this armor would take the brunt of the damage, Sakura would still get bruises underneath it if the attacks were strong enough, and judging by the incoming punch, it was going to be.
The final second before Rena's attack hit her was spent moving her arms and legs into position, attempting to block or parry every single punch that Rena threw at her, and while most of the attacks were blocked correctly, one of them made contact with her gut. The raw strength of that punch told Sakura that, at any cost, she needed to avoid taking a second one. She spent all her energy blocking or parrying every other single punch she could, having no room to counter-attack, and forgetting that she could control the lightning blades at the moment, doing every single thing in her power to not take a second punch.