Tenant waving landlord liability is not enough. Because even if tenant won't sue landlord, the injured visitor might sue landlord. The proposed clause does not prevent visitor from suing.
What you need is an indemnity clause, it says something like "The tenant shall indemnify and hold harmless any loss by the landlord arised from the tenant's business use of the premise ..." This means, even if visitor sues the landlord and landlord lost the case, the tenant will reimburse landlord such loss.
For exact language, please google "indemnity rental clause". For example see https://www.bwbllp.com/file/bwb-pu-indemnity-oct13-pdf
