Vale almost stumbled after hearing Isaac's shout.
However, he immediately understood what he was saying as he hesitated for a moment before telling her Lotus not to kill them…
'I'll just incapacitate them… They'll need weeks or months to recover.' Lotus promptly replied.
This is what Vale liked about her. She doesn't complain and just follows his instruction whatever their situation was.
'That's good enough.' Vale replied in satisfaction.
Although he wanted to kill the Variants because of his current situation, he felt that they would be at the point of no return once he killed someone in this building.
Even Headmaster Jean might try to kill him in order to appease this lunatic Dark Magic researcher.
Anyway, once he gets out of this building, he should have a better chance of escaping and he would surely get the Academy's protection.