This song isn't one of my favourites by TAD (I'm sorry!), so I haven't listened to it as in depth as most of their others, and these are just impressions:

This is a song about depression (almost a prelude to Little Miss Why So). Now, we fortunately currently live in a time where it's becoming more acceptable to be open about mental health struggles and be listened to, so of course this does not apply to all people with depression, but it is true that if someone with depression refuses to put effort into a relationship, it can have a very negative effect on the partner, and that's what I believe this song is about.

(Also, before reading, I have depression and most of this shit has applied to me in past relationships so don't think I'm attacking anyone!)

'Leave the room but you get trapped in the lift' - while observers often say 'if you're unhappy just leave', there are many things that can stop a person leaving, such as the fear of worsening their partner's depression / 'caught in the rain' - spending a lot of time with a person with depression can often cause a deterioration of one's own mental health.