Upvote:3
Well it depends on your flight.
If you're just in transit, then that's fine and legal. However, if you miss your connection, then it depends - if it's on the same ticket, that's the airline's responsibility to rebook you.
If it's a separate ticket, you have two issues. One, if you miss the connection, you lose the second flight. Secondly, if you have luggage, it likely will need to be rebooked - which means you'll have to exit transit.
So then it becomes a matter of whether or not you need a visa to exit into Belgium. This depends on your citizenship, but if you can get one on arrival, or don't need one (eg European citizen), then that's not a problem.
So legal, yes, but a risk - yes too. 35 minutes is pretty tight - it doesn't leave much room for error.