Obligation to pay the visa costs in case of early resignation

Hello Sir,

I have received an offer letter from a non-profit organisation in Abu Dhabi, UAE working with the UAE government for environment conservation.

They are offering a 12 months limited contract and I will need to reimburse them for visa, medical and medical insurance costs if I resign before the contract expiry, even if I serve a one-month notice.

My questions are:

1. Being a government entity, are they legally permitted to demand/deduct visa, medical and insurance costs from an employee? I know the labour law prohibits it.

2. I am expecting another job offer in 2-3 days time but this organisation wants me to respond to the offer ASAP.

If I accept this offer now (dont submit any ID/ passport documents), can I inform them afterwards that I am not going forward with this offer? Are there any legal implications?