Yessir, doesn't look that huge to me.
Suppose the "bridge" is the little triangular prism on top and slightly forward. Size estimates can vary greatly, but assuming those little slits are windows, the bridge could be 20m on a side, 32 tons on the lower deck, and 8 tons on the upper, which would guesstimate the ship's volume at 2,000 tons.
The airlock would then be 10-12m on a side.