Did UNetbootin Installed Something Else

i just wanted to have a USB boot-able pen drive in case of emergency, and i found that the UNet booting software could take my image and put it into a USB stick, everything seems right but when i started the process i see the "Restart" option at the 4th stepmy problem question its quite simple.WHY?why it ask me to restart? i suspect that it wast created in order that just after you finish creating the boot-able USB restart to try it but why if i don't want, i just wanted to make a copy and to save the usb stick in a safe place and continue working but what is my fear about it? and what about if that intrusive software has made any modification in my system? because no necessarily the system i use to run the program is the system i need to boot from usb..and what about this?:the software webpage says:http://unetbootin. sourceforge.net/For the Hard Disk / "frugal install" mode, UNet booting uses a Windows or Linux-based installer to install a small modification to the boot loader (bootmgr and bcdedit on Vista, grldr and boot.ini for NT-based systems, grub.exe and config.system for Win9x, or GRUB on Linux, uses the boot loader to boot the desired distribution's installer or to load the system utility, no CD required. After the distribution has been installed, or once done using the system utility, the modification to the boot-loader is then undone.