Marcellus, who owes a good deal of money to the bank, is intimidated by its imposing structure. He stands frozen on the threshold for a short moment, unwilling or unable to enter. He seems anxious.
The limen threshold plays an important part in Latin literature. In erotic elegy, the shut-out-lover spends a good deal of time on the wrong side of the threshold wishing to be let in. So much time, in fact, that there is a ancient literary term (Greek) for the genre: paraclausithyron (παρακλαυσίθυρον). Here is an example from Ovid. The translation is by Peter Green.
Who but a soldier or lover would put up with freezing
Nights – rain, snow, sleet? The first
Goes out on patrol to observe the enemy’s movements,
The other watches his rival, an equal foe.
A soldier lays siege to cities, a lover to girls’ houses,
The one assaults city gates, the other front doors.
The idea of love as conquest is all too familiar.
The bank has large glass double-doors (fores). Our Marcellus, the doors having been opened, waits on the threshold for-a-short-time (paulisper). He seems anxious.