Yes! Terrific news!
Only way I see this working is if you control another surviver of the labs, and seek to free the remaining test subjects, and possibly if there are any crew members left, them too, also, you have a chance to run into GlAdos again.
She is one of my favourite video characters of all time, up there with Saren, Sandra cohen, Molluck and Rian.
Damn I'm a sucker for anti villians.
Or possibly she could be running wild in the wilderness of the half life world, like said above, but I tend to find the half life world boring, unless you're inside a facility, like the museum, citadel and prison, or in case of portal, the apature science facility.
Wait, did the facility blow up, or just the area with GlAdos?