If you'd have some better senority, I'd say hang around. But if you're already at the bottom of the list here, then yes, leave for something else. No matter where you go you'll end up at the bottom of some other place's seniority list, on reserve.
There are some guys here who have a flying job on the side, but they keep it hush hush. Maybe the CP will give you prior permission, especially if it will help prevent you from not having the 1500.
BTW, if any of you guys in IAD ever want to take a tour of the Ramp tower, it's pretty cool and the guys working are awesome also.