Inherit Environment from Parent when launching a DEBUG container

Right now whenever we enter a DEBUG container we have a fresh environment.

For a better user experience, and also to make command checks launched by the default executor be consistent with checks launched by the command executor, we should have the DEBUG container inherit the environment from its parent container.

There are two possibilities:

1) Inheriting the env set up from the parent container when it was launched.
2) Inheriting the env from the parent container at the instant that the child container is launched (because the parent container might set some of its own environment variables once it starts up).

I think that any of those possibilities would be fine for the health checks use case, we should discuss what is better for debugging.