Future employment GC

[vamsidhar_n]

hello, I recently got a full time and the position is requiring 2,3 years of exp so they said they can file GC only in EB3 after i requested they agreed to file under EB2 as future employment and said they will offer a promotion in the mean while that will have more than 5 years of exp.So do i have to stick with them after my GC and how long.If i got promoted in the mean while can i leave the company after my GC. I mean is that a good option. I already have more than 5 years of exp and having master's degree.

Thanks,