Jason,
All of the "interior" ( as opposed to exterior, i.e. with the therapist or an obvious monologue) scenes are, for me, quite difficult to interpret. I suspect there is a lot of private symbolism that hardly anyone has the key to. A general rule of thumb is - the more white space on the page, the less obvious the meaning.
But that said, here's the way I see it. The main character has just emerged from a chemical regimen that has reduced her to a near catatonic, but has not fundamentally helped. Hatch opens/Stark light - the first time we hear this. She is very fragile and suddenly aware (again) of how flimsy and unstable her mind is. Ideas of stopping the harmful ways of thinking merge into thoughts of suicide (How do i stop?) Then Please.../Money.../Wife... with the ellipses calling attention to the act of language. The meanings of words crushes her. I read somewhere that the dotted line on the throat may be referring to an advertising image with a coupon to cut out. At any rate the rest of the scene seems to dissolve into the rhythm of madness, with some striking poetry and images that echo other scenes, but with no clear meaning or intent, at least not to me.
There are a number of lines in the play that are perplexing, though powerful. Has anyone got any idea about the "Look after your mum now" remark?