Using the shift key works. It didn’t hold the boot and join in X.
➜ ~ apt list snapd
snapd/bionic-updates,now 2.32.9+18.04 amd64 [installed]
➜ ~ snap version
snap 2.33.1
snapd 2.33.1
series 16
ubuntu 18.04
kernel 4.15.0-24-generic
➜ ~ systemd-detect-virt
none
➜ ~ uname -r
4.15.0-24-generic