Either SA has intel that Hezbollah is going to escalate and current conflict is going to expand.
It's very unlikely that SA would push ahead with the deal with the US/Israel. If they did, it would be because they felt they felt they need security guarantees asap due to Iran escalating. This would make Saudi citizens potential targets for reprisals.
Least exciting but not improbable explanation is that they'd rather be overly cautious despite there being no new intel. They're simply preparing for the seemingly inevitable ground offensive into Gaza.