You were in the disabled toilet! What were you thinking the string was for? Y’know, the bars aren’t for practicing gymnastics and getting in a quick set of dips!

Just like on "The IT Crowd," when Roy used a disabled toilet and accidentally pulled the emergency cord instead of the flush chain, so he laid on the floor, pretended to be disabled, and claimed that a man with a ginger beard mugged him and stole his wheelchair, then spent the rest of the episode having to deal with the (sitcom) consequences of lying about being disabled.