$50K biannual, or biennial? Biiiig difference.
If it's biannual, might be worth sticking around for.
Otherwise, better compare $30K+$50k+70K with how much you'll earn if you leave for DAL or FDX two years before flow... and 777 FO is going to new-hires at UAL.
Although it's a certainly a nice deal if you have a GED or several DUIs.