As of beta 2.0 there are two possible ways to get the key - but you need to choose if you kill or free the snail.
1. Killing the snail: Kill her and hit the stomach 3 times to enter the hole, pick up a note, walk to the bed and listen to the radio: which causes the hand to appear next to the snails body.
2. The Goal of the Snail is to get to the Radio Tower, to live in the underground without the need of a shell. If you have marked the Radio Tower on the map, it seems to trigger the hand appearence besides the snail. It looks like you either need to find the Tower by your own or you get a map mark from letters randomly found in the Swamp.