Kevin falls<br>Kevin is at a theme park. He goes on the big roller coaster. He is having a great time. The roller coaster goes upside down. Kevin falls out and injures himself badly.
Kevin was having a bad time until he fell out of the roller coaster, then he was having a great time.
It's definitely incorrect because he was having a great time before he fell out, and obviously you would not be having a great time after you suffered serious injuries from falling out of a roller coaster. It's difficult because the statement contains many similar words from the text, but placed in a different order to make a different meaning.
( z1 and :op ( z2 have :ARG0 ( z3 person :name ( z4 name :op "Kevin" ) ) :ARG1 ( z5 time :ARG1-of ( z6 bad ) ) :time ( z7 until :op ( z8 fall :ARG1 z3 :direction ( z9 out-of :op ( z10 roller-coaster ) ) ) ) ) :op ( z11 have :ARG0 z3 :ARG1 ( z12 time :mod ( z13 great ) ) :time ( z14 then ) ) )