Tomorrow I'll be arriving in BRU from BUD in the morning and will only have business in the city in the afternoon. Since I'll be flying back to BUD the same night, I'll already have my return boarding pass by the time I get to BRU. Will I be able to easily access the lounge (*G) and stay there for a couple of hours before heading into the city?

(Note: this was, of course, not my original intention, but I preemptively moved from the LH outbound that would've taken me to BRU slightly after 12 up to early morning direct SN flight due to the LH strike, which could've easily turned this trip into a trip in vain.)