"Upon execution of this Sublease and as security for the faithful performance by Tenant of all of the terms and conditions upon the Tenant's [i.e., Urban] part to be performed, Urban shall deposit [$638,863.50] with Royal as security hereunder. The Security Deposit shall be maintained in a segregated interest-bearing account for the benefit of Tenant. If Tenant defaults with respect to any provision of this Sublease, including, but not limited to the provisions relating to the payment of Rent, Royal may (but shall not be required to) use, apply or retain all or any part of the Security Deposit for the payment of any Rent or any other sum in default, or for the payment of any amount which Landlord [i.e., Royal] may spend or become obligated to spend by reason of Tenant's default, or to compensate Landlord for any other loss or damage which Landlord may suffer by reason of Tenant's default. . . . If Tenant faithfully performs every provision of this Sublease to be performed by it, the Security Deposit or any balance thereof shall{**53 Misc 3d at 451} be returned to Tenant (or, at Landlord's option, to the last assignee of Tenant's interest hereunder) within thirty (30) days after the expiration of the lease term." (See id. at 17 [emphasis added].)
The parties subsequently executed a rider to the sublease (the rider):
"1. Article 2.3 B is hereby modified and amended as follows: