Honest opinion is probably not. If the lease is otherwise valid and you want to use the break in as justification for not paying, the landlord would have to be in violation of the lease terms or you would need to show that the unsafe condition renders the unit uninhabitable. If the landlord has breached his/her explicit obligations in the lease or maintains it in such an unsafe manner that you have been "constructively evicted", then you would not be responsible for rent payments.
Either argument is pretty tenuous based on the limited facts you provided but I would start by scrutinizing your lease, paying special attention to any section addressing security in the building. I would also express your concerns in writing to your landlord and request specific accommodations for added security. Make sure you keep a copy of all written communication. If you pay for any added security, then you may be entitled to a reduction in your rent payments for costs that should have been the landlord's responsibility. Make sure you keep all paperwork and proof of payments. Good luck...Ask a similar question