One at a time
Nero and Isa moved from the hallway to an apartment, after Nero retrieved the Air push that was covered in a thin layer of goo. Although three of the creatures had been defeated, more could come at any time so they could not wait in the hallway. After all, fighting them off had not been a silent affair. While Nero was capable of putting up a fight, it was best to pick and choose their battles.
Nero looked out the window to see if he could determine the situation, but all he saw was a haze that covered the entire building. Either something was blocking their view, or a very heavy fog had covered the city, which was unusual for this time of year.
In that case, it might not be completely safe to exit either. But that was only for now. Nero still had faith that someone would come and rescue them sooner or later.