NOC. I can't trust my Boss...

Hi all
i am working in qatar for last five years. i am totally not happy with my current employer. Last week i got an offer with high salary from another company in qatar.

i am sure they will not allow me to join with new company. so i am planning to go to uae for searching new job thru visit visa. (My RP in qatar up to 11th December 2008. and i am planning to take emergency leave).

But my current employer will suffer when i leave this company, becoz nobody here(in this office) for my replacement and they need me really.

even if i go to uae, i can find job easly, bcoz of my experiance.

Dear friends..., my questain is..

1) After i go to dubai, can i ask my employer in qatar to provide NOC. becoz i need that new job in qatar. so that i can continue my work with my current employer also. (for a limited period only)

2) If they agreed to give NOC, is there any problem will rise after i go to qatar? (becoz i can't trust my boss..)

looking for your advise..

thanks