If my mom fell from the electric escalator because other people fell on top of her, how can we get the store to pay for my mom's medical bills?

An accident/incident report should have been filed with the store when your mom fell.  Your mom's personal injury claim should be filed with the store's insurance carrier.  When your mom completes her medical treatment and is released by the doctor or is declared by the doctor to be permanent and stationary which means having reached a point where no further improvement is anticipated, she should obtain her medical bills, medical reports and documentation of any wage loss.  Her personal injury claim filed with the store's insurance carrier should include these items.  Compensation for the medical bills is straight reimbursement.  Compensation for wage loss is straight reimbursement.  The medical reports will document the nature and extent of your mom's injuries and will be used to determine compensation for pain and suffering which is an amount in addition to the medical bills.  If your mom is dissatisfied with settlement offers from the store's insurance carrier, she should reject the settlement offers and file a lawsuit against the store for negligence.  If the case is settled with the store's insurance carrier, NO lawsuit is filed.  If the case is NOT settled with the store's insurance carrier, your mom will need to file her lawsuit against the store prior to the expiration of the applicable statute of limitations or she will lose her rights forever in the matter.