Leisurely walk in under 10 minutes. The real worry though is for those who find themselves in the B lounge and don't realise that getting the transit will dump you at arrivals . No idea how long that would take to work itself out although I guess one would need to speak to someone to see if you could somehow be allowed back airside again without going through immigration. Probably not.

Talking of A10 and buses, is A4 also a regular bus gate?