That's the problem with TWRP on this phone, it doesn't boot up properly. Currently there's no safe way to boot into it without doing the reset. I know that daemon32 said:

which might work.

 

I can get into twrp and out of it without any problem. I hold vol+ and the home button, then I hold down the power button. Holding all 3 buttons down for a few seconds, even while its booting up. I get the lg splash screen and about 2 or 3 seconds later I get a message "release all keys to enter recovery". I do that and it goes into twrp without issue. You can't reboot out of twrp though, it will factory reset. You have to power off out of twrp. You can't reboot system/bootloader/recovery from twrp or it will factory reset. Also, you can't boot into recovery from within android, it will factory reset also. You have to be completely powered off, then you can get into twrp. I'm runnin 2.8.0.0. It gives me the option to factory reset when I hold vol- and power down. Then its says to factory reset press the power button, any other key will reboot.