Not really. Most planes leak quite a bit anyway- they’re constantly running air compressors to keep it at about the equivalent pressure of 6,000-8,000 feet.
At that point, it was merely mildly concerning. If the window had blown out mid-Atlantic that would have been terrifying- flying low enough to maintain pressure would expend too much fuel, etc. but they were only 10-15 minutes into the flight; so, no big deal.
Also? At 20kft, yiu have about 30 minutes before you pass out. (Airlines typically have 10-15 minutes oxygen reserves, for a fully packed aircraft, more than enough time to dive down to breathable pressures. Even from the normal cruising altitudes of 30-40k ft)
I’m surprised there wasn’t a flashy warning thing, though. At 14k-ish pressure altitude… the oxy masks should have dropped automatically