Which is why I said that he is wearing those peril-sensitive sunglasses: if I remember correctly, they would prevent you from seeing anything that could disturb you.

No, they're so that you can maintain your cool attitude in the face of extreme danger. (Because you can't see it).

Actually at one point they are described as hiding things that might disturb you too (massive massive hitchikers fan :-))

You may be right, I'd have to check, but I thought that was the 'SEP', the somebody-elses's-problem-field.

The SEP hides things which don't fit into your worldview, the glasses hide things which might disturb you, which can fit into your worldview or not.

Ah I might be slightly off: the proper quote says (along with your bit) they hide things that might alarm you.

The radio play uses disturb.