Unlock enemy spawn rooms after finishing a defense mission

[Boffosaurus]

I recently just played my first defense mission where I had to hold off waves of baddies. I noticed that openable lockers appear in the rooms they spawn from. It's fair enough that you can't sit in those rooms and wait for them and I am fine with them being locked during the mission but much to my dismay I found myself unable to enter the rooms even after the mission had ended and even though they were lit green which I would think would indicate them being unlocked.

I'd simply like the ability to go through and clear out all of the rooms of their cash after finishing off all of the waves.

[Bang_Doll]

Or the last wave turns into an exterminate mission where you have to go in there and get them. I imagine them as doors leading to docking bays where Grineer dropships have docked with whatever ship you're on now.