It wasn't all THAT random, considering there WAS an evil monster bagpipe on the previous page.
I think it would've been more random if he maybe said, "SEXY POTATO!" or "POLKA SAUSAGE!" or "FLUFFY FUNGUS!"
“…Judge not what a man has done, but judge what he could have done if he was a different bloke altogether. For art thou a leper? And a leper can changeth his spots…” --Rudy Wade, Misfits (Series 4, Episode 8)