Low power simplex portables on 462.675 will not attract anyone's attention. Consider another radio service or better yet a cellular phone if you need personal emergency communication. Note also that GMRS repeaters may not have a phone patch facility as is common in the Amateur Radio Service. When you use GMRS for an emergency you must relay the information to another operator that has access to a telephone, providing someone actually answers your call. All stations should listen with squelch disabled before transmitting or activating a repeater.
Some licensees use simplex communication on repeater output channels.
Be courteous to other stations. Also note that GMRS is a base to mobile and mobile to base communication service. Base stations of the same or different licensees may not communicate with each other. You either have to know someone willing to add you to their system or you have to install your own. The latter can be quite expensive.