Why not write this as two separate sentences, without a semicolon?
"On yö, eikä heillä ole kiire".
Why worry? The semicolon was used flawlessly!
I believe "ei ole kiire" means "not in a hurry".
Why not kiirettä?
Busy and 'in a hurry' do not mean the same thing Duo!!!
"It's nighttime" should be allowed as well