The answer to the first one is:
Reg applied poison to the adhesive you have to lick on the envelope to seal it. He sent the envelope along with a greeting card and requested that the card be sent back in the envelope posted. Timothy licked the envelope... and died.
And the answer to amadeus's one:
She's a dwarf. She's small enough to reach the ground floor button, but she can only reach halfway up the rest of the buttons unless it's raining and she uses her umbrella or her taller friends are with her.