There's a student cafeteria (Kårcafe Aurum; lunch menu) right opposite to our lecture hall. Unfortunately, all Kårkafe-restaurants are closed on Friday, Dec 19th.
Other options listed from closest to the venue
Fabbes cafe (Finnish/urban buffet; lunch menu; route)
Assarin ullakko (student caferetia; lunch menu; route)
Several options within some 400-500 meters on Hämeenkatu (map), e.g. VG wok (Asian vegetarian menu), Kuori (global vegan), Hesburger, Subway, Delhi Darbar (Indian), Naantalin aurinkoinen (bakery/soup lunch), Afrodite (Greek), Trattoria Romana (Italian), Yummy Korean, Yangtze (Chinese), Pawon Lawu (Indonesian), Ye Shanghai (Chinese)